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This document contains for the greater part the “SON-R 2 1/2-7 Manual and ResearchReport”. Not included are chapter 12 (Directions per subtest), chapter 13 (The recordform, norm tables and computer program) and the appendices.

The reference for this text is:

Tellegen, P.J., Winkel, M., Wijnberg-Williams, B.J. & Laros, J.A. (1998).Snijders-Oomen Nonverbal Intelligence Test. SON-R 2 1 / 2-7 Manual and Research

Report . Lisse: Swets & Zeitlinger B.V.

This English manual is a translation of the Dutch manual, published in 1998 ( SON-R21 / 2-7 Handleiding en Verantwoording ). The German translation was also publishedin 1998 ( SON-R 2 1 / 2-7 Manual ). In 2007 a German manual was published withGerman norms ( SON-R 2 1 / 2-7 Non-verbaler Intelligenztest. Testmanual mit deutscher

Normierung und Validierung ).

Translation by Johanna Noordam

ISBN 90 265 1534 0

Since 2003, the SON-tests are published by Hogrefe Verlag, Göttingen, Germany.

© 1998, 2009 Publisher: Hogrefe, Authors : Peter J. Tellegen & Jacob A. Laros

http://www.hogrefe.deE-mail: verlag@hogrefe.de

Rohnsweg 25, 37085 Göttingen, Germany

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CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

PART I: THE CONSTRUCTION OF THE SON-R 2 ,,,,, -7

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.1 Characteristics of the SON-R 2 , -7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.2 History of the SON-tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.3 Rationale for the revision of the Preschool SON . . . . . . . . . . . . . . . . . . . . . . . 16

1.4 Phases of the research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.5 Organization of the manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2. Preparatory study and construction research . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.1 The preparatory study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.2 The construction research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3. Description of the SON-R 2 ,,,,, -7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.1 The subtests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.2 Reasoning tests, spatial tests and performance tests . . . . . . . . . . . . . . . . . . . . 31

3.3 Characteristics of the administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4. Standardization of the test scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.1 Design and realization of the research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.2 Composition of the normgroup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

4.3 The standardization model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.4 The scaled scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5. Psychometric characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.1 Distribution characteristics of the scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.2 Reliability and generalizability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5.3 Relationships between the subtest scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

5.4 Principal components analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

5.5 Stability of the test scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

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PART III: THE USE OF THE TEST

10. Implications of the research for clinical situations . . . . . . . . . . . . . . . . . . . . . . . . 117

10.1 The objectives of the revision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

10.2 The validity of the test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

10.3 The target groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

10.4 The interpretation of the scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

10.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

11. General directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

11.1 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

11.2 Directions and feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

11.3 Scoring the items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14011.4 The adaptive procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

11.5 The subtest score . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

11.6 Adapting the directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

12. Directions per subtest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

12.1 Mosaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

12.2 Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

12.3 Puzzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

12.4 Analogies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16312.5 Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

12.6 Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

13. The record form, norm tables and computer program . . . . . . . . . . . . . . . . . . . . 187

13.1 The use of the record form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

13 .2 The use of the norm tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

13.3 The use of the computer program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

13.4 Statistical comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Appendix A Norm tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Appendix B The record form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

Appendix C The file SONR2.DAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

Appendix D Contents of the test kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

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TABLES AND FIGURES IN THE TEXT

IntroductionTable 1.1 Overview of the versions of the SON-tests . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pilot study and construction researchTable 2.1 Relationship between the subtests of the Preschool SON and the

SON-R 2 , -7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Table 2.2 Origin of the items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Description of the SON-R 2 ,,,,, -7Table 3.1 Tasks in the subtests of the SON-R 2 , -7 . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 3.1 Items from the subtest Mosaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figure 3.2 Items from the subtest Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figure 3.3 Items from the subtest Puzzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 3.4 Items from the subtest Analogies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Figure 3.5 Items from the subtest Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Figure 3.6 Items from the subtest Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Table 3.2 Classification of the subtests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Standardization of the test scoresTable 4.1 Composition of the norm group according to age, sex and phase of research 37Table 4.2 Demographic characteristics of the norm group in comparison with the

Dutch population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Table 4.3 Education and country of birth of the mother in the weighted and

unweighted norm group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Psychometric characteristicsTable 5.1 P-value of the items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Figure 5.1 Plot of the discrimination and difficulty parameter of the items . . . . . . . . . 45Table 5.2 Mean and standard deviation of the raw scores . . . . . . . . . . . . . . . . . . . . . . 46Table 5.3 Distribution characteristics of the standardized scores in the weighted

norm group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Table 5.4 Floor and ceiling effects at different ages . . . . . . . . . . . . . . . . . . . . . . . . . . 47Table 5.5 Reliability, standard error of measurement and generalizability of the test

scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48Table 5.6 Reliability and generalizability of the IQ score of the Preschool SON, the

SON-R 2 , -7 and the SON-R 5 , -17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Table 5.7 Correlations between the subtests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Table 5.8 Correlations of the subtests with the rest total score and the square of the

multiple correlations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Table 5.9 Results of the Principal Components Analysis in the various age and

research groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Table 5.10 Test-retest results with the SON-R 2 , -7 . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Table 5.11 Examples of test scores from repeated test administrations . . . . . . . . . . . . 56

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Relationships with other variablesTable 6.1 Duration of the test administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Table 6.2 Relationship of the IQ scores with the time of administration . . . . . . . . . . 58Table 6.3 Examiner effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 6.4 Regional and local differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Table 6.5 Relationship of the test scores with sex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Table 6.6 Relationship of the IQ score with the occupational and educational level

of the parents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Table 6.7 Relationship of the IQ score with the SES level . . . . . . . . . . . . . . . . . . . . . 62Table 6.8 Relationship between IQ and country of birth of the parents . . . . . . . . . . . 63Table 6.9 Relationship between evaluation by the examiner and the IQ . . . . . . . . . . 64Table 6.10 Correlations of the total scores with the evaluation by the teacher . . . . . . . 65Table 6.11 Correlations of the subtest scores with the evaluation by the teacher . . . . 66

Research on special groupsTable 7.1 Subdivision of the research groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Table 7.2 Composition of the research groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Table 7.3 Test scores per group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71Figure 7.1 Distribution of the 80% frequency interval of the IQ scores of the various

groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Table 7.4 Relationship of the IQ scores with background variables . . . . . . . . . . . . . . 74Table 7.5 Reasons for referral of children at schools for Special Education and

Medical Daycare Centers for preschoolers, with mean IQ scores . . . . . . . 75Table 7.6 Relationship between IQ and evaluation by the examiner . . . . . . . . . . . . . 76Table 7.7 Correlations between test scores and evaluation by institute or school

staff member . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77Table 7.8 Correlations between the subtests and subtest-rest correlations . . . . . . . . . 79

Immigrant childrenTable 8.1 Test scores of native Dutch children, immigrant children and children

of mixed parentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Table 8.2 Relationship between group, SES level and IQ . . . . . . . . . . . . . . . . . . . . . . 82Table 8.3 Differentiation of mean IQ scores according to country of birth . . . . . . . . 83Table 8.4 Mean IQ scores of Surinam, Turkish and Moroccan children who had

participated in the OPSTAP(JE) project . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Relationship with cognitive testsTable 9.1 Overview of the criterion tests used and the number of children to whom

each test was administered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88Table 9.2 Characteristics of the children to whom a criterion test was administered

in the standardization research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 9.3 Correlations with other tests in the standardization research . . . . . . . . . . . 90Table 9.4 Correlations with nonverbal cognitive tests in the second year of

kindergarten, 5 to 6 years of age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

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Table 9.5 Correlations with cognitive tests completed by children at low SES schoolsgiven educational priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Table 9.6 Characteristics of the children in the special groups to whom a criteriontest was administered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Table 9.7 Correlations with criterion tests in the special groups . . . . . . . . . . . . . . . . 98Table 9.8 Correlations with the WPPSI-R in Australia . . . . . . . . . . . . . . . . . . . . . . . . 102Table 9.9 Age and sex distribution of the children in the American validation

research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Table 9.10 Correlations with criterion tests in the American research . . . . . . . . . . . . . 104Table 9.11 Correlations with the BAS in Great Britain . . . . . . . . . . . . . . . . . . . . . . . . . 105Table 9.12 Overview of the correlations with the criterion tests . . . . . . . . . . . . . . . . . . 107Table 9.13 Difference in scores between SON-IQ and PIQ of the WPPSI-R . . . . . . . . 108Table 9.14 Correlations of the Performance Scale and the Reasoning Scale with

criterion tests, for cases in which the difference between correlations wasgreater than .10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Table 9.15 Comparison between the mean test scores of the SON-R 2 , -7 and thecriterion tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 9.16 Comparisons between tests of the evaluation of the subject’s testability . . 113Table 9.17 Comparisons between tests in relation to socioeconomic and ethnic

background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114Table 9.18 Comparisons between tests in relation to evaluation of intelligence and

language skills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Implications of the research for clinical situationsTable 10.1 Mean change in IQ score over a period of one month . . . . . . . . . . . . . . . . . 118Figure 10.1 The components of the variance of the SON-R 2 , -7 IQ score . . . . . . . . . 123Table 10.2 Classification of IQ scores and intelligence levels . . . . . . . . . . . . . . . . . . . 130Table 10.3 Composition of the variance when several tests are administered . . . . . . . 132Table 10.4 Correction of mean IQ score based on administration of two or three tests 133Table 10.5 Obsolescence of the norms of the SON-IQ . . . . . . . . . . . . . . . . . . . . . . . . . 133

Record form, norm tables and computer programTable 13.1 Examples of the calculation of the subject’s age . . . . . . . . . . . . . . . . . . . . . 190Figure 13.1 Diagram of the working of the computer program . . . . . . . . . . . . . . . . . . . 195Table 13.2 Comparison between the possibilities using the computer program and

using the norm tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197Table 13.3 Examples of probability and reliability intervals for various scores . . . . . 202

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Nan JanSnijders-Oomen Snijders(1916-1992) (1910-1997)

FOREWORD

The publication of the SON-R 2 , -7 completes the third revision of the Snijders-Oomen Non-verbal Intelligence Tests. Over a period of fifty years Nan Snijders-Oomen and Jan Snijderswere responsible for the publication of the SON tests. We feel honored to be continuing theirwork. They were interested in this revision and supported us with advice until their death.

The present authors played different roles in the production of this test and the manual. PeterTellegen , as project manager, was responsible for the revision of the test and supervised theresearch. Marjolijn Winkel made a large contribution to all phases of the project in the context of her PhD research. Her thesis on the revision of the test will be published at the end of 1998. Jaap

Laros , at present working at the University of Brasilia, participated in the construction of thesubtests, in particular Mosaics and Analogies. Barbara Wijnberg-Williams , made a large contri-bution, based on her experience as a practicing psychologist at the University Hospital of Groningen, to the manner in which the test can be administered nonverbally to children withcommunicative handicaps.

The research was carried out at the department for Personality and Educational Psychology of the University of Groningen. Wim Hofstee, head of the department, supervised the project.

Jannie van den Akker and Christine Boersma made an important contribution to the organiza-

tion of the research.

The research was made financially possible by a subsidy from SVO, the Institute for Education-al Research (project 0408), by a subsidy from the Foundation for Behavioral Sciences, a section

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of the Netherlands Organization for Scientific Research (NWO-project 575-67-033), and bycontributions from the SON research fund. Wolters-Noordhoff, who previously published theSON-tests, made an important contribution to the development of the testing materials. Thedrawings for the subtests Categories, Puzzles and Situations were made by Anjo Mutsaars . Thefigures for the subtest Patterns were executed by Govert Sips of the graphical design agencySips. Wouter Veeman from Studio van Stralen executed the subtests Mosaics and Analogies.

The construction of a test requires a large number of subjects, for the construction research aswell as for the standardization and the validation. In the last few years, more than three thousandchildren were tested with the SON-R 2 , -7 in the framework of the research. We are greatlyindebted to them, as well as to their parents and the staff members of the schools and instituteswhere the research was carried out.

In the Netherlands, as well as in Australia, Great Britain and the United States of America, manystudents, researchers, and practicing psychologists and orthopedagogic specialists contributedto the research. Thanks to their enthusiasm and involvement, the research could be carried out

on such a large and international scale. Without claiming to be comprehensive, we would like tomention the following people by name:

Margreet Altena, Rachida El Baroudi, Cornalieke van Beek, Wynie van den Berg, M. van den Besselaar, Marleen Betten, Marjan Bleckman, Nico Bollen, Rene Bos, Ellen Bouwer, Monique Braat, C. Braspenning, Marcel Broesterhuizen, Karen Brok, Ankie Bronsveld, Aletha Brouwer, Anne Brouwer, Sonja Brouwer, Lucia Burnett, Mary Chaney, Janet Cooper, Pernette le Coultre-Martin, Richard Cress, J. van Daal,Shirley Dennehy, M. van Deventer, Dorrit Dickhout-Kuiper, Julie Dockrell,

Nynke Driesens, Petra van Driesum, Marcia van Eldik, Marielle Elsjan, Yvonne Eshuis, Arnoud van Gaal, Judith Gould, Marian van Grinsven, Nicola Grove, Renate Grovenstein, Marije Harsta, R.G. den Hartog, Leida van der Heide, Roel van der Helm, Marlou Heppenstrijdt, Valerie Hero, Sini Holm, Marjan Hoohenkerk, E.P.A. Hopster, Jacqueline ten Horn, Jeannet Houwing, Hans Höster, Jo Jenkinson, Jacky de Jong, Myra de Jong, Anne Marie de Jonge, José Kamminga, Jennifer Kampsnider, Claudine Kempa, Debby Kleymeer, Jeanet Koekkoek, Marianne van de Kooi, Annette Koopman, Monique Koster, A.M. Kraal,

Marijke Kuiper, Koosje Kuperus, Marijke Künzli-van der Kolk, Judith Landman, Nan Le Large, Del Lawhon, J. van Lith-Petry, Jan Litjens, Amy Louden, Henk Lutje Spelberg, Mannie McClelland, Sanne Meeder, Anke van der Meijde, Jacqueline Meijer, Sjoeke van der Meulen, Bieuwe van der Meulen, Jitty Miedema, Margriet Modderman, Cristal Moore, Marsha Morgan, Renate Mulder, Marian Nienhuis-Katz, F. Nietzen, Theo van Noort, Stephen O’Keefe,

Jamila Ouladali, Mary Garcia de Paredes, Inge Paro, Immelie Peeters, Jo Pelzer,Simone Peper, Trudy Peters-ten Have, Dorothy Peterson, Mirea Raaijmakers, Lieke Rasker, Inge Rekveld, Lucienne Remmers, E.J. van Rijn van Alkemade,Susan Roberts, Christa de Rover, Peter van de Sande, A.J. van Santen,

Liesbeth Schlichting, Marijn Schoemaker, Ietske Siemann, Margreet Sjouw, Emma Smid, L. Smits, Tom Snijders, Marieke Snippe, P. Steeksma, Han Starren, Lilian van Straten, Penny Swan, Dorine Swartberg, Marjolein Thilleman, Lous Thobokholt-van Esch, Jane Turner, Dick Ufkes, Baukje Veenstra, Nettie van der Veen, Marja Veerman, Carla Vegter, Pytsje Veltman, Harriet Vermeer, Mieke van Vleuten, Jeroen Wensink, Betty Wesdorp-Uytenbogaart, Jantien Wiersma, Aranka Wijnands, G.J.M. van Woerden, Emine Yildiz and Anneke Zijp .

With the publication of this “Manual and Research Report” of the SON-R 2 , -7, an importantphase of the revision of the test comes to an end. This does not mean that the test is ‘finished’.The value of a test is determined, for a large part, by diagnostic experiences and by ongoing

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11FOREWORD

research. We are, therefore, interested in the experiences of users, and we would appreciatebeing informed of their research results when these become available as internal or externalpublications. We intend to inform users and other interested parties about the developments andfurther research with the SON tests via Internet. The address of the homepage will be:www.ppsw.rug.nl/hi/tests/sonr.

In the last years the need to carry out diagnostic research on children at a young age has greatlyincreased. Furthermore, the realization has grown that the more traditional intelligence tests areless suitable for important groups of children because they do not take sufficient account of thelimitations of these children, or of their cultural background. In these situations the SON testsare frequently used. We hope that this new version of the test will also contribute to reliable andvalid diagnostic research with young children.

Groningen, January 1998 Dr. Peter Tellegen

Heymans InstituteUniversity of GroningenGrote Kruisstraat 2/19712 TS GroningenThe Netherlands

tel. +31 50 363 6353fax +31 50 363 6304

e-mail: p.j.tellegen@rug.nlhttp://www. testresearch.nl

Reviewing of the SON-R 2 ,,,,, -7

The test has been reviewed by de COTAN, the test commission of the NetherlandsInstitute for Psychologists. The categories used are insufficient, sufficient and good.The rating is as follows:

Basics of the construction of the test: good Execution of the materials: good Execution of the manual: good Norms: good Reliability: good

Construct validity: goodCriterion validity: good

mailto:p.j.tellegen@rug.nlhttp://www.testresearch.nl/http://www.testresearch.nl/http://www.testresearch.nl/mailto:p.j.tellegen@rug.nl

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13

1 INTRODUCTION

The new version of the Snijders-Oomen Nonverbal Intelligence Test for children from two-and-a-half to seven years, the SON-R 2 , -7, is an instrument that can be individually administered toyoung children for diagnostic purposes. The test makes a broad assessment of mental function-ing possible without being dependent upon language skills.

1.1 CHARACTERISTICS OF THE SON-R 2 ,,,,, -7

The SON-R 2 , -7, like the previous version of the test, the SON 2 , -7 (Snijders & Snijders-Oomen, 1976), provides a standardized assessment of intelligence. The child’s scores on sixdifferent subtests are combined to form an intelligence score that represents the child’s abilityrelative to his or her age group. Separate norm tables allow total scores to be calculated for theperformance tasks and for the tasks mainly requiring reasoning ability.

A distinctive feature of the SON-R 2 , -7 is that feedback is given during administration of the test. After the child has given an answer, the examiner tells the child whether it is correct orincorrect. If the answer is incorrect, the examiner demonstrates the correct answer. Whenpossible, the correction is made together with the child. The detailed directions provided in themanual also make the test suitable for the assessment of very young children. In general, theexaminer demonstrates the first items of each subtest in part or in full. Examples are included inthe test directions and items.

The items on the subtests of the SON-R 2 , -7 are arranged in order of increasing difficulty.This way a procedure for determining a starting point appropriate to the age and ability of eachindividual child can be used. By using the starting point and following the rules for discontinu-ing the test, the administration time is limited to fifty to sixty minutes.

The test can be administered nonverbally or with verbal directions. The spoken text does notgive extra information. The manner of administration can thus be adapted to the communicationability of each individual child, allowing the test to proceed as naturally as possible.

Because the test can be administered without the use of written or spoken language, it isespecially suitable for use with children who are handicapped in the areas of communication

and language. For the same reason it is also suitable for immigrant children who have little or nocommand of the language of the examiner.

The testing materials do not need to be translated, making the test suitable for internationaland cross-cultural research. The SON-tests are used in various countries. The names of thevarious subtests are shown on the test booklets in the following languages: English, German,Dutch, French, and Spanish. The manual has been published in English and German as well asin Dutch.

A similarity between the SON-R 2 , -7 and other intelligence tests for (young) children, suchas the BAS (Elliott, Murray & Pearson, 1979-82), the K-ABC (Kaufman & Kaufman, 1983), theRAKIT (Bleichrodt, Drenth, Zaal & Resing, 1984) and the WPPSI-R (Wechsler, 1989), is thatintelligence is assessed on the basis of performance on a number of quite diverse tasks. How-ever, verbal test items are not included in the SON-R 2 , -7. Such items are often dependent to agreat extent on knowledge and experience. The SON-R 2 , -7 can therefore be expected to befocused more on the measurement of ‘fluid intelligence’ and less on the measurement of ‘crys-tallized intelligence’ (Cattell, 1971) than are the other tests.

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The subtests of the SON-R 2 , -7 differ from the nonverbal subtests in other intelligence tests intwo important ways. First, the nonverbal part of other tests is generally limited to typicalperformance tests. The SON-R 2 , -7, however, includes reasoning tasks that take a verbal formin the other tests. Second, while the testing material of the performance part of the other tests isadmittedly nonverbal, the directions are given verbally (Tellegen, 1993).

An important difference with regard to other nonverbal intelligence tests such as the CPM(Raven, 1962) and the TONI-2 (Brown, Sherbenou & Johnsen, 1990) is that the latter testsconsist of only one item-set and are therefore greatly dependent on the specific ability that ismeasured by that test. Nonverbal intelligence tests such as the CTONI (Hammill, Pearson &Wiederholt, 1996) and the UNIT (Bracken & McCallum, 1998) consist of various subtests, likethe SON-R 2 , -7. A fundamental difference, however, is that the directions for these tests aregiven exclusively with gestures, whereas the directions with the SON-R 2 , -7 are intended tocreate as natural a test situation as possible.

An important way in which the SON-R 2 , -7 differs from all the above-mentioned tests isthat the child receives assistance and feedback if he or she cannot do the task. In this respect theSON-R 2 , -7 resembles tests for learning potential that determine to what extent the child

profits from the assistance offered (Tellegen & Laros, 1993a). The LEM (Hessels, 1993) is anexample of this kind of test.In sum, the SON-R 2 , -7 differs from other tests for young children in its combination of a

friendly approach to children (in the manner of administration and the attractiveness of thematerials), a large variation in abilities measured, and the possibility of testing intelligenceregardless of the level of language skill.

1.2 HISTORY OF THE SON-TESTS

The publication of the SON-R 2 , -7 completes the third revision of the test battery that NanSnijders-Oomen started more than fifty years ago. In table 1.1 the earlier versions are shown

schematically.The first version of the SON-test was intended for the assessment of cognitive functioning in

deaf children from four to fourteen years of age (Snijders-Oomen, 1943). Drawing on existingand newly developed tasks, Snijders-Oomen developed a test battery which included an assort-ment of nonverbal tasks related to spatial ability and abstract and concrete reasoning. The testwas intended to provide a clear indication of the child’s learning ability and chances of succeed-ing at school. One requirement for the test battery was that upbringing and education shouldinfluence the test results as little as possible. Further, a variety of intellectual functions had to beexamined with the subtests, and the tasks had to interest the child to prevent him or her becom-ing bored or disinclined to continue.

No specific concept of intelligence was assumed as a basis for the test battery. However,‘form’, ‘concrete coherence’, ‘abstraction’ and ‘short-term memory’ were seen as acceptablerepresentations of intellectual functioning typical of subjects suffering from early deafness(Snijders-Oomen, 1943). The aim of the test battery was to break through the one-sidedness of the nonverbal performance tests in use at the time, and to make functions like abstraction,symbolism, understanding of behavioral situations, and memory more accessible for nonverbaltesting.

The first revision of the test was published in 1958, the SON-’58 (Snijders & Snijders-Oomen, 1958). In this revision the test battery was expanded and standardized for hearing aswell as deaf children from four to sixteen years of age.

Two separate test batteries were developed during the second revision. The most importantreason for this was, in all the subtests of the original SON, a different type of test item hadseemed more appropriate for children above six years of age. The bipartite test that already

existed in fact was implemented systematically in this second revision: the SSON (Starren,1975) was designed for children from seven to seventeen years of age; for children from three toseven years of age the SON 2 , -7, commonly known as Preschool SON, or P-SON, was devel-oped (Snijders & Snijders-Oomen, 1976).

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The form and contents of the SSON strongly resembled the SON-’58, except that the SSONconsisted entirely of multiple choice tests. After the publication of the SSON in 1975, the SON-’58 remained in production because it was still in demand. In comparison to the SSON, theSON-’58 contained more stimulating tasks and provided more opportunity for observation of behavior, because it consisted of tests in which children were asked to manipulate a large varietyof test materials. The subtests in the Preschool SON maintained this kind of performance test toprovide opportunities for the observation of behavior.

The third revision of the test for older children, the SON-R 5 , -17, was published in 1988(Snijders, Tellegen & Laros, 1989; Laros & Tellegen, 1991; Tellegen & Laros, 1993b). This testreplaces both the SON-’58 and the SSON, and is meant for use with hearing and deaf childrenfrom five-and-a-half to seventeen years of age. In constructing the SON-R 5 , -17 an effort wasmade to combine the advantages of the SSON and the SON-’58. On the one hand, a range of diverse testing materials was included. On the other hand, a high degree of standardization inthe administration and scoring procedures as well as a high degree of reliability of the test wasachieved.

The SON-R 5 , -17 is composed of abstract and concrete reasoning tests, spatial ability testsand a perceptual test. A few of these tests are newly developed. A memory test was excludedbecause memory can be examined better by a specific and comprehensive test battery than by a

single subtest. In the SON-R 5 , -17, the standardization for the deaf is restricted to conversionof the IQ score to a percentile score for the deaf population. The test uses an adaptive procedurein which the items are arranged in parallel series. This way, fewer items that are either too easyor too difficult are administered. Feedback is given in all subtests; this consists of indicating

Table 1.1Overview of the Versions of the SON-Tests

SON (1943)

Snijders-Oomen Deaf Children

4-14 years

SON-’58 (1958)

Snijders & Snijders-OomenDeaf and Hearing Children

4-16 years

SON 2 ,,,,, -7 (Preschool SON ) SSON(1975) (1975)

Snijders & Snijders-Oomen StarrenHearing and Deaf Children Hearing and Deaf Children

3-7 years 7-17 years

SON-R 2 ,,,,, -7 SON-R 5 ,,,,, -17(1998) (1988)

Tellegen, Winkel, Wijnberg-Williams & Laros Snijders, Tellegen & LarosGeneral Norms General Norms2;6-8;0 years 5;6-17;0 years

– under each heading has been listed: the year of publication of the Dutch manual, the authors of themanual, the group and the age range for which the test was standardized

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whether a solution is correct or incorrect. The standardized scores are calculated and printed bya computer program.The SON-R 5 , -17 has been reviewed by COTAN, the commission of the Netherlands Institutefor Psychologists responsible for the evaluation of tests. All aspects of the test (Basics of theconstruction of the test, Execution of the manual and test materials, Norms, Reliability andValidity) were judged to be ‘good’ (Evers, Van Vliet-Mulder & Ter Laak, 1992). This means theSON-R 5 , -17 is considered to be among the most highly accredited tests in the Netherlands(Sijtsma, 1993).

After completing the SON-R 5 , -17, a revision of the Preschool SON was started, resulting inthe publication of the SON-R 2 , -7. The test was published in 1996, together with a manualconsisting of the directions and the norm tables (Tellegen, Winkel & Wijnberg-Williams, 1997).In the present ‘Manual and Research report’, the results of research done with the test are alsopresented: the method of revision, the standardization and the psychometric characteristics, aswell as the research concerning the validity of the test. Norm tables allowing the calculation of separate standardized total scores for the performance tests and the reasoning tests have been

added. Also, the reference age for the total score can be determined. Norms for experimentalusage have been added for the ages of 2;0 to 2;6 years. All standardized scores can easily becalculated and printed using the computer program.

1.3 RATIONALE FOR THE REVISION OF THE PRESCHOOL SON

The most important reasons for revising the Preschool SON were the need to update the norms,to modernize the test materials, to improve the reliability and generalizability of the test, and toprovide a good match with the early items of the SON-R 5 , -17.

Updating the normsThe Preschool SON was published in 1975. After a period of more than 20 years, revision of anintelligence test is advisable. Test norms tend to grow obsolete in the course of time. Researchshows (Lynn & Hampson, 1986; Flynn, 1987) that performance on intelligence tests increasesby two or three IQ points over a period of 10 years. Experience in the Netherlands with therevision of the SON-R 5 , -17 and the WISC-R is consistent with this (Harinck & Schoorl,1987). Comparisons in the United States of scores on the WPPSI and WPPSI-R, and scores onthe WISC-R and WISC-III showed an average increase in the total IQ scores of more than threepoints every ten years. The increase in the performance IQ was more than four points every tenyears (Wechsler, 1989, 1991).

Changes in the socio-economic environment may explain the increase in the level of perform-ance on intelligence tests (Lynn & Hampson, 1986). Examples of these changes are watching

television, increase in leisure time, smaller families, higher general level of education, changes inupbringing and education. The composition of the general population has also changed; in theNetherlands the population is ageing and the number of immigrants is increasing. The norms of the Preschool SON from 1975 can be expected to provide scores that are too high, and that nolonger represent the child’s performance in comparison to his or her present age group.

The testing materialsThe rather old-fashioned testing materials were the second reason for revising the test: some of the drawings used were very dated, and the increasing number of immigrant children in theNetherlands over the last twenty years makes it desirable to reflect the multi-cultural back-ground of potential subjects in the materials (see Hofstee, 1990). The structure of the materialsand the storing methods of the test were also in need of improvement.

Improving the reliability and generalizabilityA third motive for revision was to improve the reliability and generalizability of the PreschoolSON, especially for the lower and upper age ranges. Analysis of the data presented in the manual

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of the Preschool SON showed that the subtests differentiated too little at these ages. The range of possible raw scores had a mean of 12 points. In the youngest age group, 20% of the childrenreceived the lowest score on the subtests and in the oldest age group, 43% received the highestscore (Hofstee & Tellegen, 1991). In other words, the Preschool SON was appropriate for chil-dren of four or five years old, but it was often too difficult for younger children and too easy forolder children. Further, there was no standardization at the subtest level, only at the level of thetotal score; this meant that it was not possible to calculate the IQ properly if a subtest had not beenadministered. Finally, the norms were presented per age group of half a year. This could lead to adeviation of six IQ points if the age did not correspond to the middle of the interval.

Correspondence with the SON-R 5 ,,,,, -17To be able to compare the results of the SON-R 2 , -7 with those of the SON-R 5 , -17, the newtest for young children should be highly similar to the test for older children. An overlap in theage ranges of the tests was also considered desirable. This way, the choice of a test can be basedon the level of the child, or on other specific characteristics that make one test more suitablethan the other. Various new characteristics of the SON-R 5 , -17, such as the adaptive test

procedure, the standardization model and the use of a computer program, were implemented asfar as possible in the construction of the SON-R 2 , -7.

1.4 PHASES OF THE RESEARCH

On the basis of the above-mentioned arguments it was decided to revise the Preschool SON. Therevision was not restricted to the construction of new norms; the items, subtests and directionswere also subjected to a thorough revision. The revision proceeded in several phases. Thissection presents a short review of the research phases.

Preparatory studyIn the preparatory study the Preschool SON was evaluated. This started in 1990. The aim of thepreparatory study was to decide how the testing materials of the Preschool SON could best beadapted and expanded. To this end, users of the Preschool SON were interviewed, the literaturewas reviewed, other intelligence tests were analyzed and a secondary analysis of the data of thestandardization research of the Preschool SON was performed.

Construction research phaseThe construction research for the SON-R 2 , -7 took place in 1991/’92. During this period, threeexperimental versions of the test were administered to more than 1850 children between twoand seven years of age. The final version of the SON-R 2 , -7 was compiled on the basis of thedata from this research, the experiences and observations of examiners, and the comments and

suggestions of psychologists and educators active in the field.

Standardization research phaseThe standardization research, in which more than 1100 children in the age range two to sevenyears participated, took place during the school year 1993/’94. The results of this researchformed the basis for the standardization of the SON-R 2 , -7, and the evaluation of its psycho-metric characteristics. During the standardization research, background data relevant for theinterpretation of the test scores were collected.

For the validation of the test, other language and intelligence tests were administered to alarge number of the children who participated in the standardization research. Administration of these tests was also made possible by collaboration with the project group that was responsible

for the standardization of the Reynell Test for Language Skills (Van Eldik, Schlichting, LutjeSpelberg, Sj. van der Meulen & B.D. van der Meulen, 1995) and the Schlichting Test forLanguage Production (Schlichting, Van Eldik, Lutje Spelberg, Sj. van der Meulen & B.F. vander Meulen, 1995).

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Validation research phaseSeparate validation research was done for the following groups: children in special educationalprograms, children at medical preschool daycare centers, children with a language, speech and/or hearing disorder, deaf children, autistic children and immigrant children. Validation researchwas also carried out in Australia, the United States of America and the United Kingdom. Theresults of these children on the SON-R 2 , -7 have been compared with their performance onmany other cognitive tests.

1.5 ORGANIZATION OF THE MANUAL

This manual is made up of three parts. In the first part the construction phase of the test isdiscussed. Chapter 2 deals with the preparatory study and the construction research duringwhich new testing materials and administration procedures were developed. In chapter 3 adescription is given of the subtests and the main characteristics of the administration of the test.The standardization research and the standardization model used are described in chapter 4.

Information about psychometric characteristics such as reliability, factor structure and stabilitycan be found in chapter 5.

In the second part research concerning the validity of the test is described. Chapter 6 is basedon the results in the norm group and discusses the relations between test performance and othervariables, such as socio-economic level, sex and evaluations by the examiner and teachers. Inchapter 7 the test results in a number of special groups of children, with whom the SON-tests areoften used, are discussed. The special groups include children with a developmental delay,autistic children, language, speech and/or hearing disabled children, and deaf children. Chapter8 deals with the performance of immigrant children. In chapter 9 the correlations between theSON-R 2 , -7 and several other tests for intelligence, language skills, memory and perceptionare discussed. The research on validity involved both children in regular education and handi-capped children, and was partly carried out in other countries.

The third part of this book concerns the practical application of the test. Chapter 10 dealswith the implications of the research results in practice, and with problems that can arise withthe interpretation of the results. The general directions for the administration and scoring of thetest are described in chapter 11; the directions for the separate subtests can be found in chapter12. Chapter 13 gives guidelines for using the record form, the norm tables and the computerprogram.

In the appendices the norm tables for determining the reference age, and the standardizedsubtest and total scores can be found, as well as an example of the record form and a descriptionof the contents of the test kit.

In general, ages in the text and tables are presented in years and months. This means that 4;6

years equals four years and six months. In a few tables the mean ages are presented with adecimal; this means that 4.5 years is the same as 4;6 years. In the norm tables the age of 4;6years indicates an interval from ‘four years, six months, zero days’ to ‘four years, six months,thirty days’ inclusive.

To improve legibility, statistical results have been rounded off. This can lead to seeminglyincorrect results. For instance a distribution of 38.5% and 61.5% becomes, when rounded off,39% and 62%, and this does not add up to 100%. Similar small differences may occur in thepresentation of differences in means or between correlations.

Pearson product-moment correlations were used in the analyses. Unless stated otherwise,the correlations were tested one-sidedly.

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Comparative research on the Preschool SON, the Stanford-Binet and parts of the WPPSI wasconducted by Harris in the United States of America. In general, her assessment of the test waspositive. Her criticism focused on some of the materials and the global norm tables (Harris, 1982).

Secondary analyses of the standardization dataThe original data from a sample of hearing children (N=503) involved in the standardizationresearch of the Preschool SON was used for the secondary analyses. A study was made of thedistribution of the test scores according to age, the correlation between the test scores and thereliability. The results were as follows:

– The standard deviation of the raw subtest scores was usually highest in children from four tofive years of age. For Mosaics and Copying, the range of scores for young children from 2;6to 4 years was very restricted. For most subtests the range decreased greatly in the oldestgroups from 5;6 to 7 years.

– In the conversion of the scores into IQ scores, the distributions were not sufficiently normal-ized, so that they were negatively skewed for children from five years onwards. This couldresult in extremely low IQ scores.

– The reliability for combinations of age groups was recalculated. After this, a correction forage was carried out. The mean reliability of the subtests was .57 for children from 2;6 to fouryears of age, .66 for children from four to five years, and .61 for children from 5;6 to sevenyears. The reliability of the total score was .78 for children from 2;6 to four years, .86 forchildren from four to five years, and .82 for children from 5;6 to seven years. Generally, thereliability was low, especially for the youngest and oldest age groups where strong floor andceiling effects were present. The reliability of the subtests and the total scores was muchlower than the values mentioned in the manual of the Preschool SON. The cause of thisdiscrepancy was that, in the manual, the reliability was calculated for combined age groupswith no correction for age.

– The generalizability of the total score is important for the interpretation of the IQ scores. Inthis case, the subtests are seen as random samples from the domain of possible, relevantsubtests. The generalizability coefficient of the Preschool SON was .61 for the age groupfrom 2;6 to four years, .75 for the age group from four to five years and .65 for the age groupfrom 5;6 to seven years.

– The reliability of the subtest Memory was low and the score on this subtest showed a lowcorrelation with age and with the scores on the remaining subtests.

Review of the literatureIn the revision of the Preschool SON we attempted to produce a version that was compatible withthe early items of the SON-R 5 , -17. As the subtest Analogies in the SON-R 5 , -17 is one of itsstrongest components, the possibility of developing a similar analogy test for young children wasexamined. Based on recent research results (Alexander et al., 1989; Goswami, 1991) it seemed

possible to construct an analogy test for children from about 4 years of age onwards. Since ananalogy test would most likely be too difficult for the youngest children, starting this test withsorting seemed advisable; the level of abstraction required for sorting is lower than the level of abstraction required for understanding analogies, and, in a certain sense, precedes it.

Implications for the revisionThe results of the preparatory study confirmed the need for a new standardization and athorough revision of the Preschool SON. An important goal in the revision of the PreschoolSON was the improvement of the psychometric characteristics of the test. The reliability andthe generalizability of the test scores were lower than was desirable, especially in theyoungest and oldest of the age groups for which the test was designed. However, an increasein reliability could not be gained simply by expanding the number of items and subtestsbecause an increase in the duration of the test could lead to fatigue, loss of motivation anddecrease in concentration. Any expansion of the test had therefore to be combined with aneffective adaptive procedure.

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2.2 THE CONSTRUCTION RESEARCH

In 1991/’92, extensive research was done with three experimental versions of the test. Thesewere administered to more than 1850 children between two and eight years of age. The researchwas carried out in preschool play groups, day care centers and primary schools across theNetherlands. The versions were also administered on a small scale to deaf children and childrenwith learning problems. The examiners participating in the construction research were mainlytrained psychologists with experience in testing. Psychologists and educators who normallymake diagnostic assessments of young children were contacted in an early phase to obtaininformation about the usability of the construction versions for children with specific problems.More than twenty people in the field, employed by school advisory services, audiologicalcenters and outpatient departments, administered sections of the three versions to a number of children. They commented on and gave suggestions for the construction of the material, thedirections and the administration procedure.

Points of departure for the construction

The most important objectives in the construction and administration of the experimentalversions were:

– expanding the number of items and subtests to improve the reliability of the test and to makethe test more suitable for the youngest and the oldest age groups,

– limiting the mean administration time to a maximum of one hour by using an effectiveadaptive procedure,

– making the testing materials both attractive for children and durable, – developing clear directions for the administration of the test and the manner of giving feed-

back.

Testing materialsFrom the first experimental version on, the test consisted of the following subtests: Mosaics,Categories, Puzzles, Analogies, Situations and Patterns. This sequence was maintained through-out the three versions. Tests that are spatially oriented are alternated with tests that requirereasoning abilities, and abstract testing materials are alternated with materials using concrete(reasoning) pictures. Mosaics is a suitable test to begin with as it requires little direction, thechild works actively at a solution, and the task corresponds to activities that are familiar to thechild.

The items of the experimental versions consisted of (adapted) items from the Preschool SONand the SON-R 5 , -17 and of newly constructed items. Most of the new items were very simpleitems that would make the test better suited to young children. Table 2.2 shows the origin of theitems in the final version of the test. Of a total of 96 items, five of which are example items, 45%are new, 25% are adaptations of Preschool SON items, and 30% are adaptions from the SON-R

5 , -17.In the first experimental version the original items of the Preschool SON and the SON-R

5 , -17 were used. In the following versions all items of the subtests were redrawn andreformed to improve the uniformity of the material and to simplify the directions for thetasks. In the pictures of people the emphasis was on pictures of children and care was takento have an even distribution of boys and girls. More children with a non-western appearancewere included.

An effort was made to make the material colorful and attractive, durable and easy to store. Amat was used to prevent the material from sliding around, to facilitate picking up the pieces andto increase the standardization of the test situation.

Adaptive procedure and duration of administrationTo make the test suitable for the age range from two to seven years, a broad range of taskdifficulty is required. An adaptive test procedure is desirable to limit the duration of the test, andto prevent children having to do tasks far above or far below their level. Having to do items that

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are much too difficult is very frustrating and demotivating for children. When older children aregiven items that are much too easy, they very quickly consider these childish and may then beinclined not to take the next, more difficult items seriously.

In the Preschool SON a discontinuation rule of three consecutive mistakes was used.Because the mistakes had to be consecutive, children sometimes had to make many mistakesbefore the test could be stopped. In practice this meant that, especially with young children,examiners often stopped too early. In the SON-R 5 , -17 the items are arranged in two or threeparallel series and in each series the test is discontinued after a total of two mistakes. In the firstseries the first item is taken as a starting point; in the following series the starting point dependson the performance in the previous series. This method has great advantages: everyone starts thetest at the same point, but tasks that are too easy as well as tasks that are too difficult are skipped.

Further, returning to an easier level in the next series is pleasant for the child after he or she hasdone a few tasks incorrectly.Research was carried out with the first experimental version to see if the adaptive method of

the SON-R 5 , -17 could also be applied with the SON-R 2 , -7. The problem was, however, thatthe subtests consist of two different parts. This makes a procedure with parallel series confusingand complicated because switching repeatedly from one part of the test to the other may benecessary. In the subsequent construction research, only one series of items of progressivedifficulty was used. However, the discontinuation criterion was varied and research was done onthe effect of using an entry procedure in which the item taken as a starting point depended on theage of the child.

Finally, on the basis of the results of this research, a procedure was chosen in which thefirst, third or fifth item is taken as a starting point and each subtest is discontinued after atotal of three mistakes. The performance subtests can also be discontinued when two subse-quent mistakes are made in the second section of these tests. The items in these subtests havea high level of discrimination, and the children require a fair amount of time to complete thetasks. They become frustrated if they have to continue when the next item is clearly toodifficult for them.

As a result of the adaptive procedure, the number of items to be administered is strictlylimited, and the mean duration of the test is less than an hour, but very little information is lostby skipping a few items. Further, the children’s motivation remains high during this procedurebecause only a very few items above their level are administered.

Difficulty of items and ability to discriminate

After each phase of research the results were analyzed per subtest with the 2-parameter logisticmodel from the item response theory (IRT; see Lord, 1980; Hambleton & Swaminathan, 1985).The program BILOG (Mislevy & Bock, 1990) was used for this analysis. With this program theparameters for difficulty and discrimination of items can be estimated for incomplete tests. The

Table 2.2Origin of the Items

Subtests of the SON-R 2 ,,,,, -7

Origin Mos Cat Puz Ana Sit Pat Total

Adapted fromthe Preschool SON 3 4 6 3 2 6 24

Adapted fromthe SON-R 5 , -17 6 9 – 5 9 – 29

New items 7 3 9 10 4 10 43

Total number of items,including examples 16 16 15 18 15 16 96

PREPARATORY STUDY AND CONSTRUCTION RESEARCH

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IRT-model was used because the adaptive administration procedure makes it difficult to evalu-ate these characteristics on the basis of p-values and item-total correlations. The parameter fordifficulty indicates a level of ability at which 50% of the children solve the item correctly; theparameter for discrimination indicates how, at this level, the probability that the item will beanswered correctly increases as ability increases.

Because of the use of an adaptive procedure, it was important that the items wereadministered in the correct order of progressive difficulty; the examiner had to be reasonablycertain that items skipped at the beginning would have been solved correctly, and that itemsskipped at the end would have been solved incorrectly. Also important was a balanceddistribution in the difficulty of the items, and sufficient numbers of easy items for youngchildren and difficult items for older ones. On the basis of the results of the IRT-analysis,new items were constructed, some old items were adapted and others were removed from thetest. In some cases the order of administration was changed. A problem arising from this wasthat items may become more difficult when administered early in the test. The help andfeedback given after an incorrect solution may benefit the child so that the next, moredifficult item becomes relatively more easy.

Directions and feedbackAn important feature of the SON-tests is that directions can be given verbally as well asnonverbally. This makes the test situation more natural because the directions can correspond tothe communication skills of the child. When verbal directions are given, care must be taken notto provide extra information that is not contained in the nonverbal directions. However, nonver-bal directions have their limitations, so that explaining to the children exactly what is expectedof them is difficult, certainly with young children. Examples were therefore built into the firstitems to give the child the opportunity to repeat what the examiner had done or to solve a similartask. As the test proceeds, tasks are solved more and more independently. To make the items of the SON-R 5 , -17 suitable for this approach, they were also adapted, for example, by firstworking with cards that have to be arranged correctly instead of pointing out the correct alter-native.

Not only does the difficulty of the items increase in the subtests, the manner in which theyare administered changes as well. In the construction research this procedure was continuouslyadapted, and the directions were improved in accordance with the experiences and comments of the examiners and of practicing psychologists. The greatest problems in developing clear direc-tions arose in the second section of the subtest Analogies. Here the child has to apply a similartransformation to a figure as is shown in an example. This is difficult to demonstrate non-verbally because of the high level of abstraction, but it can be explained in a few words. The testtherefore provides first for extensive, repeated practice on one example, and then provides anexample with every following item.

The feedback and help given after an incorrect solution is important in giving the child a

clear understanding of the aim of the tasks. The manner in which feedback and help should begiven was worked out in greater detail during the research and is described in the directions.

Scoring PatternsIn the subtest Patterns lines and figures must be copied, with or without the help of preprinteddots. Whether the child can draw neatly or accurately is not important when copying, butwhether he or she can see and reproduce the structure of the example is. This makes highdemands on the assessment and a certain measure of subjectivity cannot be excluded. Duringthe construction research, a great deal of attention was paid to elucidating the scoring rules, andinter-assessor discrepancies were used to determine which drawings were difficult to evaluate.On this basis, drawings that help to clarify the scoring rules were selected. These drawings areincluded in the directions for the administration of Patterns.

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3 DESCRIPTION OF THE SON-R 2 ,,,,, -7

The SON-R 2 , -7 is a general intelligence test for young children. The test assesses a broadspectrum of cognitive abilities without involving the use of language. This makes it especiallysuitable for children who have problems or handicaps in language, speech or communication,for instance, children with a language, speech or hearing disorder, deaf children, autistic chil-dren, children with problems in social development, and immigrant children with a differentnative language.

A number of features make the test particularly suitable for less gifted children and childrenwho are difficult to test. The materials are attractive, the tasks diverse. The child is given thechance to be active. Extensive examples are provided. Help is available on incorrect responses,and the discontinuation rules restrict the administration of items that are too difficult for thechild.

The SON-R 2 , -7 differs in various aspects from the more traditional intelligence tests, incontent as well as in manner of administration. Therefore, this test can well be administered asa second test in cases where important decisions have to be taken, on the basis of the outcome of a test, or if the validity of the first test is in doubt.

Although the reasoning tests in the SON-R 2 , -7 are an important addition to the typicalperformance tests, the nonverbal character of the SON tests limits the range of cognitiveabilities that can be tested. Other tests will be required to gain an insight into verbal

development and abilities. However, for those groups of children for whom the SON-R2 , -7 has been specifically designed, a clear distinction must be made between intelligenceand verbal development.

After describing the composition of the subtests, the most important characteristics of the testadministration are presented in this chapter.

3.1 THE SUBTESTS

The SON-R 2 , -7 is composed of six subtests:

1. Mosaics,2. Categories,3. Puzzles,4. Analogies,5. Situations and6. Patterns.The subtests are administered in this sequence. The tests can be grouped into two types:reasoning tests (Categories, Analogies and Situations) and more spatial, performance tests(Mosaics, Puzzles and Patterns). The six subtests consist, on average, of 15 items of increas-ing difficulty. Each subtest consists of two parts that differ in materials and/or directions.In the first part the examples are included in the items. The second part of each subtest,except in the case of the Patterns subtest, is preceded by an example, and the subsequentitems are completed independently. In table 3.1 a short description is given of the tasksin both sections of the subtests. In figures 3.1 to 3.6 a few examples of the items arepresented.

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Mosaics (Mos)The subtest Mosaics consists of 15 items. In Mosaics, part I, the child is required to copy severalsimple mosaic patterns in a frame using three to five red squares. The level of difficulty isdetermined by the number of squares to be used and whether or not the examiner first demon-strates the item.

In Mosaics II, diverse mosaic patterns have to be copied in a frame using red, yellow and red/yellow squares. In the easiest items of part II, only red and yellow squares are used, and thepattern is printed in the actual size. In the most difficult items, all of the squares are used and thepattern is scaled down.

Categories (Cat)Categories consists of 15 items. In Categories I, four or six cards have to be sorted into twogroups according to the category to which they belong. In the first few items, the drawings onthe cards belonging to the same category strongly resemble each other. For example, a shoe or aflower is shown in different positions. In the last items of part I, the child must him or herself identify the concept underlying the category: for example, vehicles with or without an engine.

Categories II is a multiple choice test. In this part, the child is shown three pictures of objectsthat have something in common. Two more pictures that have the same thing in common havethen to be chosen from another column of five pictures. The level of difficulty is determined by

the level of abstraction of the shared characteristic.

Puzzles (Puz)The subtest Puzzles consists of 14 items. In part I, puzzle pieces must be laid in a frame to

Table 3.1Tasks in the Subtests of the SON-R 2 , -7

Task part I Task part II

Mosaics Copying different simple Copying mosaic patterns inmosaic patterns in a frame, a frame, using red, yellowusing red squares. and red/yellow squares.

Categories Sorting cards into two groups Three pictures of objects haveaccording to the category to something in common.which they belong. From a series of five pictures,

two must be chosen that have thesame thing in common.

Puzzles Puzzle pieces must be laid Putting three to six separatein a frame to resemble a puzzle pieces together togiven example. form a whole.

Analogies Sorting disks into two Solving an analogy problem bycompartments on the basis applying the same principleof form and/or color of change as in the exampleand/or size. analogy.

Situations Half of each of four pictures One or two pieces are missing inis printed. The missing drawing of a situation.halves must be placed with The correct piece(s) must be chosenthe correct pictures. from a number of alternatives.

Patterns Copying a simple pattern. Copying a pattern in which five, nineor sixteen dots must be connected bya line.

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resemble the given example. Each puzzle has three pieces. The first few puzzles are firstdemonstrated by the examiner. The most difficult puzzles in part I have to be solved independ-ently.

In Puzzles II, a whole must be formed from three to six separate puzzle pieces. No directionsare given as to what the puzzles should represent; no example or frame is used. The number of puzzle pieces partially determines the level of difficulty.

Figure 3.1 Items from the Subtest Mosaics

Item 3 Item 9 Item 14(Part I) (Part II) (Part II)

Figure 3.2 Items from the Subtest Categories

Item 4 Item 11(Part I) (Part II)

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Analogies (Ana)The subtest Analogies consists of 17 items. In Analogies I, the child is required to sort three,four or five blocks into two compartments on the basis of either form, color or size. The childmust discover the sorting principle him or herself on the basis of an example. In the first few

items, the blocks to be sorted are the same as those pictured in the test booklet. In the last itemsof part I, the child must discover the underlying principle independently: for example, largeversus small blocks.

Analogies II is a multiple choice test. Each item consists of an example-analogy in which ageometric figure changes in one or more aspect(s) to form another geometric figure. Theexaminer demonstrates a similar analogy, using the same principle of change. Together with thechild, the examiner chooses the correct alternative from several possibilities. Then, the child hasto apply the same principle of change to solve another analogy independently. The level of difficulty of the items is related to the number and complexity of the transformations.

Situations (Sit)

The subtest Situations consists of 14 items. Situations I consists of items in which one half of each of four pictures is shown in the test booklet. The child has to place the missing halvesbeside the correct pictures. The first item is printed in color in order to make the principle clear.The level of difficulty is determined by the degree of similarity between the different halvesbelonging to an item.

Situations II is a multiple choice test. Each item consists of a drawing of a situation with oneor two pieces missing. The correct piece (or pieces) must be chosen from a number of alter-natives to make the situation logically consistent. The number of missing pieces determines thelevel of difficulty.

Patterns (Pat)The subtest Patterns consists of 16 items. In this subtest the child is required to copy anexample. The first items are drawn freely, then pre-printed dots have to be connected to makethe pattern resemble the example. The items of Patterns I are first demonstrated by the examinerand consist of no more than five dots.

Figure 3.3 Items from the Subtest Puzzles

Item 3 Item 11(Part I) (Part II)

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Figure 3.5 Items from the Subtest Situations

Item 5(Part I)

Item 10(Part II)

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The items in Patterns II consist of five, nine or sixteen dots and have to be copied by the childwithout help. The level of difficulty is determined by the number of dots and whether or not thedots are pictured in the example pattern.

3.2 REASONING TESTS, SPATIAL TESTS ANDPERFORMANCE TESTS

Reasoning testsReasoning abilities have traditionally been seen as the basis for intelligent functioning (Carroll,1993). Reasoning tests form the core of most intelligence tests. They can be divided intoabstract and concrete reasoning tests. Abstract reasoning tests, such as Analogies and Catego-ries, are based on relationships between concepts that are abstract, i.e., not bound by time orplace. In abstract reasoning tests, a principle of order must be derived from the test materialspresented, and applied to new materials. In concrete reasoning tests, like Situations, the object isto bring about a realistic time-space connection between persons or objects (see Snijders,Tellegen & Laros, 1989).

Spatial testsSpatial tests correspond to concrete reasoning tests in that, in both cases, a relationship within aspatial whole must be constructed. The difference lies in the fact that concrete reasoning testsconcern a meaningful relationship between parts of a picture, and spatial tests concern a ‘form’relationship between pieces or parts of a figure (see Snijders, Tellegen & Laros, 1989; Carroll,

1993). Spatial tests have long been integral components of intelligence tests. The spatial sub-tests included in the SON-R 2 , -7 are Mosaics and Patterns. The subtest Puzzles is moredifficult to classify, as the relationship between the parts concerns form as well as meaning. Weexpected the performance on Puzzles and Situations to relate to concrete reasoning ability.

Figure 3.6 Items from the Subtest Patterns

Item 6 Item 13 Item 16(Part I) (Part II) (Part II)

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However, the correlations and factor analysis show that Puzzles is more closely associated withMosaics and Patterns (see section 5.3)

Performance testsAn important characteristic that Puzzles, Mosaics and Patterns have in common is that the itemis solved while manipulating the test stimuli. That is why these three subtests are called per-formance tests. In the three reasoning tests (Situations, Categories and Analogies), in contrast,the correct solution has to be chosen from a number of alternatives. For the rest, the six subtestsare very similar in that perceptual and spatial aspects as well as reasoning ability play a role inall of them.

The performance subtests of the SON-R 2 , -7 can be found in a similar form in otherintelligence tests. However, only verbal directions are given in these tests. Reasoning tests canalso regularly be found in other intelligence tests, but then they often have a verbal form (such asverbal analogies).

In table 3.2 the classification of the subtests is presented. The empirical classification, in which

a distinction is made between performance tests and reasoning tests, is based on the results of principal components analysis of the test scores of several different groups of children (seesection 5.4). In table 3.2. the number of each subtest indicates the sequence of administration;the sequence of the subtests in the table is based on similarities of content. This sequence is usedin the following chapters when presenting the results.

Table 3.2Classification of the Subtests

No Abbr Subtest Content Empirical

6 Pat Patterns Spatial insight Performance test1 Mos Mosaics Spatial insight Performance test3 Puz Puzzles Concrete reasoning Performance test5 Sit Situations Concrete reasoning Reasoning test2 Cat Categories Abstract reasoning Reasoning test4 Ana Analogies Abstract reasoning Reasoning test

3.3 CHARACTERISTICS OF THE ADMINISTRATION

In this section the most important characteristics of the SON-R 2 , -7 are discussed.

Individual intelligence testMost intelligence tests for children are administered individually. The SON-R 2 , -7 follows thistradition for the following reasons:

– the directions can be given nonverbally, – feedback can be given in the correct manner, – testing can be tailored to the level of each individual child, – the examiner can encourage children who are not very motivated or cannot concentrate;personal contact between the child and the examiner is essential for effective testing, certainlyfor children up to the age of four to five years.

Nonverbal intelligence testThe SON-R 2 , -7 is nonverbal. This means that the test can be administered without the use of spoken or written language. The examiner and the child are not required to speak or write andthe testing materials have no language component. One is, however, allowed to speak during the

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test administration, otherwise an unnatural situation would arise. The manner of administrationof the test depends on the communication abilities of the child. The directions can be givenverbally, nonverbally with gestures or using a combination of both. Care must be taken whengiving verbal directions that no extra information is given.

No knowledge of a specific language is required to solve the items being presented. How-ever, level of language development, for example, being able to name objects, characteristicsand concepts, can influence the ability to solve the problems correctly. Therefore the SON-R2 , -7 should be considered a nonverbal test for intelligence rather than a test for nonverbalintelligence.

DirectionsAn important part of the directions to the child is the demonstration of (part of) the solution to aproblem. An example item is included in the administration of the first item on each subtest, anddetailed directions are given for all first items. Once the child understands the nature of the task,the examiner can shorten the directions for the following items. If the child does not understandthe directions, they can be repeated.

In the second part of each subtest an example is given in advance. Once the child understandsthis example, he or she can do the following items independently.

FeedbackThe examiner gives feedback after each item. In the SON-R 5 , -17, feedback is limited totelling the child whether his of her answer is correct or incorrect. In the SON-R 2 , -7 theexaminer indicates whether the solution is correct or incorrect, and, if the answer is incorrect,he/she also demonstrates the correct solution for the child. The examiner tries to involve thechild when correcting the answer, for instance, by letting him or her perform the last action.However, the examiner does not explain why the answer was incorrect.

By giving feedback, a more normal interaction between the examiner and the child occurs,and the child gains a clearer understanding of the task. The child is given the opportunity tolearn and to correct him or herself. In this respect a similarity exists between the SON-tests andtests for learning potential (Tellegen & Laros, 1993a).

Entry procedure and discontinuation ruleEach subtest begins with an entry procedure. Based on age and, when possible, the estimatedcognitive level of the child, a start is made with the first, third or fifth item. This procedure waschosen to prevent children from becoming demotivated by being required to solve too manyitems that are below their level. The design of the entry procedure ensures that the first items thechild skips would have been solved correctly. Should the level chosen later appear to be toodifficult, the examiner can return to a lower level. However, because of the manner in which thetest has been constructed, this should occur infrequently.

Each subtest has rules for discontinuation. A subtest is discontinued when a total of threeitems has been incorrectly solved. The mistakes do not have to be consecutive. The threeperformance subtests are also discontinued when two consecutive mistakes are made in thesecond part. Frequent failure often has a drastically demotivating effect on children and canresult in refusal to go on.

Time factorThe speed with which the problems are solved plays a very subordinate role in the SON-R2 , -7. A time limit for completing the items is used only in the second part of the performancetests. The time limit is generous. Its goal is to allow the examiner to end the item. The construc-tion research showed that children who go beyond the time limit are seldom able to find acorrect solution when given more time.

Duration of test administrationThe administration of the SON-R 2 , -7 takes about 50 minutes (excluding any short breaks

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during administration). During the standardization research the administration took betweenforty and sixty minutes in 60% of the cases. For children with a specific handicap, the adminis-tration takes about five minutes longer. For children two years of age, administration time isshorter; nearly 50% of the two-year-olds complete the test in less that forty minutes.

StandardizationThe SON-R 2 , -7 is meant primarily for children in the age range from 2;6 to 7;0 years. Thenorms were constructed using a mathematical model in which performance is described as acontinuous function of age. An estimate is made of the development of performance in thepopulation, on the basis of the results of the norm groups (see chapter 4). These norms run from2;0 to 8;0 years. In the age group from 2;0 to 2;6 years, the test should only be used forexperimental purposes. In many cases the test is too difficult for children younger than 2;6years. Often, they are not motivated or concentrated enough to do the test. However, in the agegroup from 7;0 to 8;0 years, the test is eminently suitable for children with a cognitive delay orwho are difficult to test. The easy starting level and the help and feedback given can benefitthese children. For children of seven years old who are developing normally, the SON-R 5 , -17

is generally more appropriate.The scaled subtest scores are presented as standard scores with a mean of 10 and a standarddeviation of 3. The scores range from 1 to 19. The SON-IQ, based on the sum of the scaledsubtest scores, has a mean of 100 and a standard deviation of 15. The SON-IQ ranges from 50 to150. Separate total scores can be calculated for the three performance tests (SON-PS) and thethree reasoning tests (SON-RS). These have the same distribution characteristics as the IQscore. When using the computer program, the scaled scores are based on the exact age; in thenorm tables age groups of one month are presented. With the computer program, a scaled totalscore can be calculated for any combination of subtests.

In addition to the scaled scores, based on a comparison with the population of children of thesame age, a reference age can be determined for the subtest scores and the total scores. Thisshows the age at which 50% of the children in the norm population perform better, and 50%perform worse. The reference age ranges from 2;0 to 8;0 years. It provides a different frame-work for the interpretation of the test results, and can be useful when reporting to persons whoare not familiar with the characteristics of deviation scores. The reference age also makes itpossible to interpret the performance of older children or adults with a cognitive delay, forwhom administration of a test, standardized for their age, is practically impossible and notmeaningful.

As with the SON-R 5 , -17, no separate norms for deaf children were developed for theSON-R 2 , -7. Our basic assumption is that separate norms for specific groups are only requiredwhen a test discriminates against a special group of children because of its contents or themanner in which it is administered. Research using the SON-R 2 , -7 and the SON-R 5 , -17with deaf children (see chapter 7) shows that this is absolutely not the case for deaf children

with the SON tests.

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4 STANDARDIZATION OF THE TEST SCORES

Properly standardized test norms are necessary for the interpretation of the results of a test. Thetest norms make it possible to assess how well or how badly a child performed in comparison tothe norm population. The norm population of the SON-R 2 , -7 includes all children residing inthe Netherlands in the relevant age group, except those with a severe physical and/or mentalhandicap. The standardization process transforms the raw scores into normal distributions witha fixed mean and standard deviation. This allows comparisons to be made between children,including children of different ages. Intra-individual comparisons between performances ondifferent subtests are also possible. As test performances improve very strongly in the age rangefrom two to seven years, the norms should ideally be related to the exact age of the child and notto an age range, as is the case for most intelligence tests for children.

4.1 DESIGN AND REALIZATION OF THE RESEARCH

Age groupsEleven age groups, increasing in age by 6 months, from 2;3 years to 7;3 years formed the pointof departure for the standardization research. In each group one hundred children were to betested: fifty boys and fifty girls. When selecting the children, an effort was made to keep the age

within each group as homogeneous as possible. The age in the youngest group, for instance, wassupposed to deviate as little as possible from two years,