The Research Enterprise

The Research Enterprise in SLP/A

• Only 1% are full-time researchers• Classes, lectures, textbooks

– information is gained through the eyes of the professor; eyes of the authors

– therefore, need to develop own critical decisions about research by reading original sources

– Letters to the Editor is another source for facilitating development of critical decision making

Clinicians need to have enough familiarity with research to judge whether the claims are reasonable and to determine just how closely the proposed clinical procedures adhere to the research methods and the underlying theory. Informed clinicians need not be sophisticated researchers, but they should have had first-hand experience with research during their graduate education to help them understand the limitations and the possibilities of research and the decisions that face researchers at so many turns in the conduct of a study.Siegel (1996)

Research-Practice Relationship (Logemann, 2000)

There are comments that I find disturbing, but luckily, hear only occasionally. The clinician, for instance, who says, “I don’t read journals because they’re all research and that’s over my head.” Or the researcher who says, “It’s unimportant whether a clinician reads my research or not, because it’s really for other researchers.”

Myths about Published Research

• “You must be a statistician to read the literature”

• “If it is in print, it must be good”

• “The more difficult to read, the more scholarly an article must be”

The Method of Science (Kerlinger & Lee, 2000)

Scientific research is a systematic, controlled, empirical, amoral, public, and critical investigation of natural phenomena. It is guided by theory and hypotheses about the presumed relations among such phenomena.– Systematic and controlled imply that the

scientific investigation is tightly disciplined and conducted in a manner that methodically rules out alternative explanations of a particular finding.

Empiricism vs Rationalism

Scientific research depends on a complex interplay of two distinct lines of inquiry:

empiricism and rationalism

These are two different philosophies that guide research

Two Modes of Inquiry in Behavioral Science

Empiricism• assumes that

knowledge must be gained through experience

• relies on inductiveinductive reasoning which uses evidence from specific cases to make inferences about general principles

Rationalism• assumes that

knowledge must be gained through the exercise of logical thought

• relies on deductivedeductive reasoning which uses general principles to make inferences about specific cases

Empiricism vs Rationalism (con’t)• Uses evidence from

particular cases to make inferences about general principles (specific cases -> general principles)

• Experiments first, then theories emerge inductively from data

• Uses general principles to make inferences about specific cases (general principles -> specific cases)

• Theory first, then test deductively by experimentation

Empiricism vs Rationalism (con’t)

• Explanations based on evidence gained from observations of phenomena, and critical evaluations of the accuracy of observations is necessary before the observations can be accepted into the realm of knowledge

• Concrete, empirical, experiential observations

• Explanations based on logical criticism of propositions which are necessary for the acceptance of explanations into the realm of knowledge

• Abstract, formal, analytical endeavors

The Research Enterprise in CDIS:

Scientific research directed toward “basic research” or “applied research”

Scientific Research

Basic Research Applied Research- development of a - used to solve some

knowledge base some social or economic

problem

Types of Research

Historical Descriptive ExperimentalUses documentary Examines group Examines causa-evidence to identify differences, trends tion through patterns or relationships observation of

among variables the effects of theusing laboratory manipulation ofmeasurements certain variables on other variables undercontrolled conditions

Two Categories of Theories (Philosophies)

Induction• empiricism• specific case

general principles• bottom-up• knowledge gained

through experience

• Skinner

• Deduction• rationalism• general principles

specific cases• top-down• knowledge gained

through logical thought

• Chomsky

Steps in Research

1. Statement of the Problem2. Method of investigation

a. Subjects/participantsb. Materialsc. Procedures

3. Results of investigation4. Conclusions

Variables in Empirical Research

• Variables are measurable quantities that vary or change under different circumstances

• can be classified in one of 3 ways1. Independent vs Dependent variables2. Active vs Attribute variables3. Continuous vs Categorical variables

Independent vs Dependent Variables

Independent Variables

• IV is the presumed cause of the DV

• is the antecedent• CAUSES change in

the behavior• you manipulate

the IV

Dependent Variables• DV is the presumed

effect• is the consequent• is the behavior that

has CHANGED• you measure the

change in the DV

Active vs Attribute Variables

Active Variable• can be

manipulated• is the IV

Attribute Variable• is an existing,

non-changing variable (e.g., I.Q., age, gender)

• usually the DV, but can be an IV in descriptive research

Continuous vs Categorical Variables

Continuous Variable• can be measured

along a continuum that reflects a rank ordering of values of the variable (e.g., frequency of stuttering, mild-severe)

Categorical Variable• cannot be

measured along a continuum

• the values of the variable can only be categorized or named (e.g., Stutterer vs Non-stutterer)

Experimental ResearchUsed to investigate cause-and-effect

relationships among variables 4 characteristics of experimental

research:• starts with a purpose, question, or

hypothesis• CONTROLS events and therefore observes

CHANGES in behavior• is repeatable• can measure effects on certain variables

by manipulating other variables– must be cautious to control “extraneous

variables”

Classification of Research

Classification of experimental research on basis of:

1. number of IVs2. number of

values of the IVs

Bivalent Experiments• Experimenter studies the effect of 2

values of one IV on the DV• The IV is manipulated so that only 2

values of the IV is presented to the Ss• experimenter selects only two of

many values that fall along a continuum of the IV to be manipulated

• for categorical variables, only two categories of the IV are selected to be manipulated

Multivalent Experiments• Experimenter studies the effects of

several values of the IV on the DV• at least 3 values of the IV are

presented to the Ss• gives a broader picture of the

relationship between the IV and DV because experimenter samples the range of possible values of the IV more thoroughly

• therefore can identify a curvilinear function

Multivalent Experiments (con’t)

EX: Ho: increases in the intensity of masking noise will cause a decrease in stuttering frequency•IV: masking noise

–LEVELS: quiet, 10, 50, 90dB

•DV: stuttering frequency

Parametric Experiments

• Researcher studies the simultaneous effects of more than one IV on the DV

• the second IV is called the parameter• can examine two main effects on the

DV as well as an interaction between the two IV in causing changes in the DV– EX: effect of distance and syllable word

pattern on lipreading ability.

Descriptive Research

Does not lead to a cause-and-effect identification between IV and DV

6 Types of descriptive research:• comparative research• developmental research• correlational research• survey research• case study• retrospective research

Comparative Research

• Measures behavior of two or more types of subjects in order to identify similarities and differences between them– EX: children with and without PD to

examine syntactic performance

Developmental Research

• Measures changes over time in the behavior or characteristics of subjects

• 3 types of developmental research– cross-sectional– longitudinal– semi-longitudinal

Correlational Research

• Studies the relationship among two or more variables by examining the degree to which changes in one variable correspond with or can be predicted from variations in another– EX: relationship between syntax and

phonology. As syntactic complexity increases, what happens in phonology?

Survey Research

• Examines conditions, practices, or attitudes through questionnaires, interviews, or a combination of the two

Case Study

• Examines an individual in detail rather than as part of a group

Retrospective Research

• Examines data already on file formulating a research problem