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The Value of Longitudinal data: using the British Cohort Studies to understand women’s employment from a life course perspective Dr Jane Elliott Research Director (NCDS and BCS70) Centre for Longitudinal Studies 29 th June 2006
Structure of presentation The four British Birth Cohort Studies The value of cohort data The 1958 cohort (National Child Development Study) Gendered aspirations at age 11 (combining qualitative and quantitative methods) Occupation and Fertility Women’s employment behaviour after the birth of a child
British Birth Cohort Studies Fully representative samples of the British population Based on one week’s births - approximately 17,000 babies Followed up from birth into adulthood Four British Birth Cohort Studies 1946 : National Survey of Health and Development (MRC funded) 1958 : National Child Development Study 1970 : British Cohort Study 1970 2000/1: Millennium Cohort Study Housed at CLS
Birth Cohort Study Representative sample of over 17,000 infants born in March 1958 Not initially planned as a longitudinal study Sample followed at ages 7, 11, 16, 23, 33, 42, 46 (prospective study) Retrospective life history data collected at age 23, 33, 42, 46 For example work history partnership history fertility history housing history Approximately 12,000 individuals are still participating Information on individuals can be linked from birth and childhood through into adult life Now funded by ESRC with data collected every four years
NCDS follow-ups and sources of information
Hypothetical life history x Born st Child nd Child 1987 Age 7 Age Age Age 46 Age 16 Age Age 33 Gets married Parents’ social class Parental interest in school work Free school meals Mother smoking Parental divorce Maths and reading tests Teachers’ assessment of child’s behaviour Exam results Job 1Job 2Job 3 Voting behaviour Psychological well being Working hours preferences Savings Domestic division of labour Union membership Training and skills Aspirations
Research questions best addressed by cohort data Long term outcomes of experiences and decisions in early life Medium and short-term outcomes & links between different life domains (e.g. health and employment) Descriptions of individual trajectories – careers, relationships, fertility, poverty and disadvantage The links between social change and the changing experiences of different cohorts Intergenerational transmission of advantage and disadvantage and the processes involved
NCDS 11-year old Essays At age 11, in 1969 NCDS Cohort members completed a short questionnaire (at school) about leisure interests, preferred school subjects and expectations on leaving school They were also asked to write an essay on the following topic: ‘Imagine you are now 25 years old. Write about the life you are leading, your interests, your home life and your work at the age of 25. (You have 30 minutes to do this).’ essays completed, mean length 204 words Copies of the original essays (in children’s handwriting) are available on microfiche at CLS and are currently being digitised.
Existing research on the essays A small sample of 521 essays have been coded for word count Boys 180 words Girls 228 words All essays have been coded for employment aspirations, over 90% give a classifiable occupation No other systematic coding and analysis of the essays has been carried out to date
Research project funded by the Nuffield foundation (Elliott and Morrow) Project is intended as a pilot study, if successful to be followed up by larger application to ESRC Aim to type up and code a sub-sample of 560 essays & conduct preliminary descriptive analyses Sample stratified to reflect: gender; ability; social class; family structure Essays will be coded for themes such as: family life; leisure; employment; housing expectations; contact with parents; pets; transport and travel; aspirations vs expectations Both qualitative and quantitative analysis will be carried out using NVIVO.7 and SPSS to help organize, code, and analyze the data Main research questions: how do gender and social class shape children’s aspirations?
Home experiences 46% of the eleven-year-olds were living in owner-occupied accommodation while 42% were in council housing 44% of children had their own bedroom 19% of girls and 16% of boys shared a bed with another member of the family 61% of mothers reported being in work at some time since the child was seven (only 3.2% were in professional or managerial occupations, compared with 20% of fathers) 66% of mothers reported that the father took an equal role in ‘managing’ the child and a further 24% described the father as having a significant role
School experiences (1969) The majority of children were in primary schools when they wrote the essays Only 4% of children were at independent schools At age 11 the median class size was 36 pupils (mean 34.3), while at age 7 the median class size had been 37 with a mean of 82% of children were in a school with a male head- teacher 45% of children had a female class teacher
Preliminary analysis (139 essays coded) Girls are slightly more likely than boys to say they will be married at age 25 (56% vs. 48%) Girls and boys are equally likely to say that they want children (45% vs. 42%) Girls are more likely than boys to write about domestic labour (65% vs. 25%) Girls are more likely than boys to mention their husband/wife’s occupation (20% vs. 10%)
282044A I am making dinner for Paul my husband and Sally my young daughter. I think I will make us all Shepherds pie and carrots. I car hear him coming down the garden path, I had better hurry up. “Hello Kathyryn what are we have-ing for dinner?,” asked Paul has he walked into the kitchen. I brought Sally in from the garden and wash her hands, then sat her in her high chair. “Has every-thing been aright at the shop?” Paul works in a butchers shop and he has just been promoted to the manger of five will known shops. After we had eaten the shepherds pie and Sally had eaten her bacon and chicken baby food I started serving the blomonge.
Serial number: Y I am 25 years of age, I live in a big house it has five bedrooms, dining room, lounge, and kitchenet. I have a wife and two children, a big jagur car which is just big enough to hold the family. The children are two boys, very energetic, they love swimming and rugby. My wife is a type that can mix with anybody, she is a good bridge, and very pasent, she is a good nurse when the children hurt themselves. The names of the family are Brian, Kevin, the twins, Edith my wife and me, Bobby. The doors of the house are orange and round the windows of the door white, the window frames are painted cream. We have oil fired central heating and an electric cooker, and strip lighting in the kitchenet. My wife does not work because I bring plenty money home from were I work, I work at the catterpiller factory at Birtleys I work as a pot spot welder, because I do the work of putting the holds through the bits of steel that make the catterpiller tracks. Each piece of steel weighs 1 ton each. I get payed £31 a week and the firm payes my petrol bill.
223004D I have two children one 4 the other 6. I am working in a school as a teacher. My husband is an Estate Agent. In the evenings we have tea and each person tells the rest about any interesting avents which has happened to them. Then we have a sit and talk about what we are going to buy or if we are going to buy a house or not. We then watch Calendar and the news. At half past seven the children will have a bath and be put to bed. Meanwhile my husband will be seeing that the car’s engine is all right so that we shall not be stranded any where is something goes wrong. After that I shall do the ironing or washing or any other jobs that want doing. At Eleven oclock we shall go to bed and get up at seven oclock. At eight oclock I would take the children one to school with me the other to her granma’s. My husband goes to work at nine o’clock. At school I [illegible] teach first English, Maths and Art. In the afternoon P.E., Projects and History.
The salience of occupation Understanding heterogeneity of women Recognise differences between women in terms of fertility and working patterns Move away from voluntaristic accounts and notion of innate differences Crompton & Harris suggest that occupations may provide ‘a major social filter through which the lives of individuals and families are structured’(1998 p 299)
Professionals vs. Managers Professionals License to practice/credentials obtained externally Long term planning of career possible More flexible working arrangements Educated to at least degree level Managers Careers forged in organisation Careers less well planned Fewer opportunities for part-time work May not be so highly educated
Cross-national work by Crompton and Harris focusing on bankers and doctors Occupation impacts on the way that women combine paid employment and family life Compared with professionals, managers Have fewer children Adopt less traditional division of labour
Results from Crompton and Harris cross- national study % of women with two or more children Doctors54% Bankers32% % of women with a traditional domestic division of labour Doctors73% Bankers46% From
Limitations of Crompton and Harris’ empirical work Relatively small (non-random) sample Focus on case study of retail banking vs medical profession Differences between the two groups in terms of Professionals vs. managers Public vs. private Levels of feminisation Levels of qualifications Cross-sectional study Analysis of NCDS data can ameliorate many of these problems
Analyses using NCDS (1958 cohort) Advantages of using NCDS Bigger & more representative sample Longitudinal data & ability to control for fertility aspirations Multivariate analysis predicting having children Logistic regression including occupation, views on having children at age 23, level of highest qualification
Occupational variations in number of children Data from Crompton and Harris study % women with two or more children Doctors54% Bankers32% Data from NCDS (1958 cohort) % of graduate women with children Professionals75% Managers64%
Predicting who has had children BS.E.Sig.Exp(B) Want kids (age 23)? 0.00 Don't know No SOC90 Major group 0.00 Managers (ref cat)ref Professionals Assoc prof & tech Clerical Craft & related Personal service Sales Machine operatives Other Not working Qualifications Degree by age Constant N=4934 women aged 42 from NCDS sweep 6
N=361 graduate women aged 42 from NCDS sweep 6
In summary NCDS (1958 cohort study) shows Differences in family building between managers and professionals No differences in domestic division of labour
Women and employment: previous research Major change in British society since the 1950s has been increase in numbers of women in the labour market A growing body of research has focused on the length of time between childbirth and returning to paid employment. Joshi and Hinde (1993);Dex, Joshi, Macran, McCulloch (1998); Blank (1989);Joesch (1994) Emphasise that the age of the youngest child is the most important determinant of women’s participation. Highly educated women display the greatest continuity in employment across the childbearing years. Growing polarisation between women
However... The majority of existing research has not distinguished between part-time and full-time employment not fully exploited the temporal features of longitudinal data not explicitly looked at duration effects
Key Research Questions Are the processes of returning to part-time work and full-time work different? Is part-time employment a bridge into full-time employment? Are there significant duration effects such that the longer a woman stays out of the labour market the more difficult it is for her to return? Are there significant interaction effects between duration and other variables. i.e. do the influences of some factors change over time within individual careers?
Research approach Uses retrospective life history data from NCDS to focus on women’s employment and fertility careers Examine transitions between episodes of Full time employment Part-time employment Non-employment Emphasis on duration effects and time varying covariates Focus on whole work history since leaving full time education, not just on transitions after child birth
State Transition Matrix based on women’s work histories from the National Child Development Survey
Approach to Event History analysis Data is available for each month of women’s life histories between age 16 and 33. This data was discretised to form a data matrixdata matrix Logistic regression was used to estimate models to indicate which factors were associated with transitions back into the labour market. Logistic regression models do not allow for the link between woman/months at the level of the individual woman. More sophisticated ‘mixture’ models i.e. random effects models were therefore estimated using the SABRE software to exploit the structure of the data.
Models estimated Models estimated focused on moving back into the labour market not employed -> full-time not employed-> part-time part-time->full time Logistic regression models initially estimated showed negative duration effects (i.e. pooled cross sectional models) Mixture models estimated allowing for unobserved individual heterogeneity indicated that the initial models were miss specified
Summary of main results from mixture models
Narrative elements of cohort studies Allow us to trace lives through time & understand how childhood circumstances may impact on adult outcomes In the 1958 cohort study, essays at 11 provide insights into children’s own narratives about their lives Potentially allow for the construction of individual case studies based on detailed information collected over the years (while preserving confidentiality) Allow for a focus on the historical context which has helped shape individual experiences Comparisons between cohorts can enable the development of a narrative about social change