Segregation change: Longitudinal evidence from the NCDS and the ONS Longitudinal Study

Dr Daniel Guinea-MartinLongitudinal Development TeamOffice for National Statistics

Introduction

• Aims• Definitions • Structural changes/changes in occupational

classification• Data

– Comparing LS & NCDS cohorts

• Occupational segregation by sex in the 1990s – At the aggregated level – At the individual level

• The importance of data comparison• Next steps

Aims

• To study occupational segregation by sex in England and Wales during the 1990s at both the aggregated and individual levels.

• To do so by using a variety of data sources.

• Why? So that they compensate each other’s weaknesses.

– At the aggregated level: Census, ONS LS, LFS– At the individual level: ONS LS and NCDS.

Definitions

Key concepts at the aggregated level:

– Overall Segregation– Vertical Segregation (See Blackwell, L. and D. Guinea-Martin, ‘Occupational segregation

by sex and ethnicity in England and Wales’, Labour Market Trends, December 2005, Vol. 113, No. 12, pp. 501-16

Key concept at the individual level: sex-typed occupations

– Male occupations (0-29 % female)– Integrated occupations (30-69 % female)– Female occupations (70-100 % female)

4 most male, integrated and female occupations in 1991 and 2001 (Unit Group Level)

2001 (SOC2000)112 Clerks of works 5216 Pipe fitters597 Coalmining workers 5321 Plasterers924 Paviors, kerb layers 8141 Scaffolders932 Slingers 5312 Bricklayers174 Restaurant/catering managers 2441 Public service admin prof271 Archivists/curators 3539 Business assoc prof nec. 350 Legal service occs 3442 Sport coaches/instructors412 Debt collectors 1142 Customer care managers661 Beuticians 9244 School midday assistants341 Midwives 6113 Dental nurses450 Medical secretaries 4211 Medical secretaries451 Legal secretaries 3212 Midwives

1991 (SOC90)

Structural changes/changes in occupational classification from 1991 to 2001

• ‘Tightening’ the application of the title ‘manager’

• Increase in jobs related to information and communication technologies

• Recognition of growth of jobs related to, e.g., environmental protection/conservation, arts, media and sports/fitness.

• In manufacturing: Increase of technically qualified jobs /reduction of craft-related occupations

• Increase in sales and after-sales occupations and in occupations in call centres.

Levels SOC90 SOC2000

Major Group 9 9

Sub-Major Group 22 25

Minor Group 77 81

Unit Group 371 353

Data used (1)

Census Longitudinal Study

1971

1981

1991

2001

+ events

+ events

+ events

+ events

1991

2001

10 % x-section

100 % x-section

n = 500,000

(late 1950s cohort n= 19,152)

1991

2001

n = 60,000

1996

LFS

1991

1999/2000

n = 17,415 /10,979

NCDS

1974

1981

1969

1965

1958

Comparing the LS and the NCDS

• The LS is used to assess the representativeness of the NCDS sample, with specific reference to the occupation-related variables.

• Levels of ‘attrition’ in the LS and NCDS cohorts

– 11.1 per cent lost-to-follow-up from 1991 to 2001 in the LS

– 12.8 per cent attrited from 1991 to 1999/2000 in the NCDS

Economic activity in 1991

0 10 20 30 40 50 60 70 80

full_tim

part_tim

self-emp

unemploy

student

sick

housewif

ls5789men ncdsmen ls5789women ncdswomen

Economic activity in 1999/2001

0 10 20 30 40 50 60 70 80

full_tim

part_tim

selfem_f

selfem_p

unemploy

student

sick

housewif

ls5789men ncdsmen ls5789women ncdswomen

People in work by sex, cohort and year (II)

Percentage of cohort members in work in 1991 and in 1999/2001

88.21

61.75

91.91

68.65

88.25

76.19

92

79.82

0 10 20 30 40 50 60 70 80 90 100

ls men

ls women

ncds men

ncds women

In work 91 In work 01

Occupation in 1991

0 5 10 15 20 25 30

Managers

Professional occs

Assoc. professionals

Clerical occs

Craft occs

Personal&protective occs

Sales occs

Plant&Machine occs

Other

ls5789men ncdsmen ls5789women ncdswomen

Occupation in 2001

0 5 10 15 20 25 30

Managers

Professional occs

Assoc. professionals

Clerical occs

Craft occs

Personal&protective occs

Sales occs

Plant&Machine occs

Other

ls5789men ncdsmen ls5789women ncdswomen

Number of sex-typed occupations (at unit groups level) by major groups in 1991 Census (SOC90)

Major Groups Male Integrat. Female Total Col % intManagers 25 17 2 44 20.0Professional occs 26 11 5 42 12.9Assoc. professionals 23 14 11 48 16.5Clerical occs 1 5 14 20 5.9Craft occs 60 10 2 72 11.8Personal&protective occs 12 6 14 32 7.1Sales occs 5 6 5 16 7.1Plant&Machine occs 48 13 1 62 15.3Other 29 3 3 35 3.5Total 229 85 57 371

Source: 10 per cent 1991 Census

Occupational sex segregation over time (standardised Gini indices)

1971 1981 1991 1996 2001 2001 (CO70) (CO80) (SOC90) (SOC90) (SOC2000) (SOC90)

Census - - 0.78 - 0.69 -

LFS - - 0.76 0.75 0.72

ONS LS 0.81 0.80 0.77 - 0.70 0.72 (no person imputation)

Occupational sex segregation over time for two cohorts born in late 1950s

1991 1999/2001 2001 (SOC90) (SOC90) (SOC2000)

aged 31-34 aged 41-44 aged 41-44

NCDS Stan. Gini 0.80 0.80Stan. MM 0.66 0.65

Index of Diss. 60.7 60.1

ONS LS Stan. Gini 0.78 0.77 0.76Stan. MM 0.65 0.62 0.62

Index of Diss. 59.4 57.1 56.9

Occupations making most difference between LS&NCDS cohorts in 1999/2001

LS/NCDS diff

SOC90 codes (Minor group) absdiff cumu. men women absdiff cumu. men women

41 Numerical clerks 3.98 3.98 110 392 6.41 6.41 33 268 2.42

12 Specialist managers 2.33 6.31 473 259 4.68 11.09 297 103 2.35

21 EngineerS 4.34 10.65 382 29 2.65 13.74 111 5 1.69

87 Road transport ope. 5.19 15.84 444 23 3.93 17.67 181 23 1.26

65 Childcare occs 7.33 23.17 5 542 8.40 26.07 1 312 1.07

34 Health assoc. prof. 5.30 28.47 58 441 6.29 32.36 15 247 0.99

72 Sales assistants 6.38 34.85 73 534 5.47 37.83 22 223 0.91

30 Scientific technicians 1.58 36.43 169 38 0.67 38.50 46 18 0.91

32 Computer analysts 0.52 36.95 74 29 1.40 39.90 72 15 0.88

23 Teaching professionals 3.53 40.48 205 445 4.29 44.19 128 278 0.76

LS Cohort (2001) NCDS Cohort (1999/2000)

2001 ID = 57.1 1999/2000 ID = 60.1

Sex by sex-typed occupations in 1991 and 2001 (Column percentages)

LS cohort

Men Women Total Men Women Total Men Women TotalMale occs 73.47 12.52 47.65 72.93 12.74 44.28 64.27 8.59 37.78

Integrated occs 19.34 26.14 22.22 19.68 24.87 22.15 27.89 29 28.42

Female occs 7.19 61.34 30.13 7.39 62.39 33.57 7.83 62.41 33.8

100 100 100 100 100 100 100 100 100

NCDS cohort

Men Women Total Men Women TotalMale occs 72.01 11.4 45.02 71.87 10.32 42.19

Integrated occs 21.58 26.95 23.97 21.89 27.53 24.61

Female occs 6.41 61.65 31.01 6.24 62.15 33.2

1991 SOC90 2001 SOC90

1991 SOC90 2001 SOC90 2001 SOC2000

Next steps

• Using the strength of the NCDS: work histories

• Apply Survival Analysis to study the influence of sex-type of occupation on duration in employment:

– How long people stay on an occupation depending on what sex-type of occupation it is?