Here you can search our series of working papers, dating back to 1983. These papers use data from our four cohort studies and cover a wide range of topics, from social inequalities and mobility, to physical health, education and cognitive development. Other papers in the series seek to improve the practice of longitudinal research. At the present time, we are only able to accept papers if at least one author is a member of the CLS research team. Some of the working papers below will subsequently have been published in peer-reviewed journals.
For more information about our working papers series, please email us at email@example.com.
Jenny Neuberger, Heather Joshi and Shirley Dex use data from the Millennium Cohort Study (MCS) to explore the pay penalty to motherhood in Britain.
Key words: Millennium Cohort Study, part-time work, motherhood, child care.
This CLS working paper examines differences in how income is collected in a nationally representative birth cohort, the Millennium Cohort Study (MCS). It looks at variations by questions asked and by respondent characteristics before then examining the implications different methods of collecting and reporting income may have for measuring poverty.
Key words: Income, survey data collection, poverty
Helen Knight, Matt Brown, Brian Dodgeon, Barbara Maughan, Martin Richards, Jane Elliott, Barbara Sahakian and Trevor Robbins explore theories within cognitive epidemiology which suggest that environmental and lifestyle factors may have a positive or negative effect on cognitive ability at different stages in life. A neurobiological explanation for this is known as the cognitive reserve hypothesis.
This hypothesis is explored through analysis of cognitive test results at age 50 on NCDS cohort members, using a lifecourse approach taking into account childhood predictors and health behaviours.
Keywords: NCDS, cognition, cognitive reserve, lifecourse, lifestyle, health behaviours.
Lisa Calderwood, Ian Plewis, Sosthenes Ketende and Rebecca Taylor evaluate the effectiveness of fieldwork strategies to covert refusals using evidence from a randomised experiment implemented on the UK Millennium Cohort Study. The authors show that intensive re-issuing is an effective way of increasing the proportion of refusals converted to a productive interview and hence increasing the sample size and reducing the refusal rate. It is also shown that refusal conversion may have led to a reduction in non-response bias in the survey estimates for several key variables.
Keywords: non-response: fieldwork intervention: cohort study: treatment effects: Millennium Cohort Study.
Matt Brown and Helen Knight explain the results of an exercise where a sub-sample of National Child Development Study members were invited to participate in a pilot study to investigate the potential of conducting neuropsychological assessments with purposive subsamples of the British Birth Cohort Studies. On completion of the assessments participants completed a short questionnaire which included a number of questions gathering views about participating in research studies involving Magnetic Resonance Imaging (MRI) scanning. The project ran from July 2009 to September 2010.
When planning the pilot study consideration was given to the inclusion of functional MRI scanning for a subset of participants, but in the end this was not feasible. The network did, however, provide an opportunity to discuss the ethical challenges associated with conducting this kind of research and one of the outputs is a full ethical review of the issues raised by the use of MRI scanning (and DNA analysis) in birth cohort studies.
Keywords: NCDS, 1958 cohort, MRI, consent, research ethics.
Lisa Calderwood focuses on the problem of locating mobile families in the Millennium Cohort Study (MCS) and examines what proportion of families who move between waves are successfully located through the study’s tracking procedures. She also examines the effectiveness of techniques designed to pick up address changes prior to the start of fieldwork for a particular wave compared with interviewer tracking in the field and investigates some of the factors associated with success or failure to locate mobile families. The paper shows that over 90% of mobile families were successfully located between wave 2 and wave 3 of the study with 55% located before the start of fieldwork for second wave. Although some differences are found in the observable demographic and socioeconomic characteristics of mobile and non-mobile families, very few of these characteristics are associated with the success or failure to locate families.
Keywords: MCS, Millennium cohort, attrition bias, non-response, tracking.
John McDonald and Sosthenes Ketende discuss nonresponse weight adjustments for sweep 3 of the UK Millennium Cohort Study (MCS). Weight adjustments are available for monotone patterns of nonresponse, where the nonresponse weight is the inverse of the estimated probability of response based on a logistic regression model, which uses data from previous sweeps to predict response at the current sweep. For non-monotone patterns, some cases have missing data for previous sweeps and this approach cannot be easily applied. For MCS, 7.5% of the families took part in sweeps 1 and 3, but not sweep 2, i.e., a non-monotonic pattern of nonresponse for 1,444 families.
The authors’ approach to estimate a nonresponse weight for MCS sweep 3 was to use multiple imputation to impute the required missing values at sweep 2 for these 1,444 families for the logistic model for response at sweep 3. This imputation used information from sweeps 1 and 3 and only involved imputing the missing values for time-varying variables shown to be predictive of nonresponse in MCS. This resulted in the multiple imputation of nonresponse weights at sweep 3, which can be averaged to produce a single nonresponse weight or the 10 imputed nonresponse weights can used for separate analyses and the results combined using Rubin’s rules. The advantages and disadvantages of both approaches are discussed.
Keywords: MCS, Millennium cohort, attrition bias, non-response.
Samantha Parsons looks at the reasons why respondents have remained, or not, in the NCDS study and what strategies help improve retention. The paper presents findings from qualitative interviews with 170 men and women who have participated in the longitudinal 1958 National Child Development Study for half a century.
Keywords: NCDS, 1958 cohort, attrition bias, non-response, sub-study, qualitative.
Sosthenes Ketende, John McDonald and Shirley Dex focus on a longitudinal study that had been relatively neglected in terms of analyses of non-response: the 1970 British Cohort Study (BCS70). They first examine non-response at successive waves, then investigate whether there is anything to learn about response from the fact that sub-studies were carried out on these data at different points over its lifetime. There us also a brief introductory review of findings from analyses of non-response in other longitudinal data sets.
Keywords: BCS70, 1970 cohort, attrition bias, non-response, sub-studies.
Jane Elliott, Sam Parsons, Andrew Miles and Mike Savage provide an overview of the design of a qualitative sub-study of 170 members of the 1958 British Birth Cohort Study (NCDS), carried out in 2008-9. The sub-study investigated the association between individuals’ social mobility experiences and the patterns of social participation, providing a resource for other researchers wishing to use this data set. The authors reflect on the methodological advantages and disadvantages posed by conducting qualitative biographical interviews with a sub-sample of members of an existing longitudinal quantitative study. Transcribed interviews from this project have been archived at the UK Data Service, so that they are available for analysis by other researchers.
Keywords: NCDS8, 58 cohort, qualitative, social mobility, social capital.
Matt Brown uses data collected from members of the National Child Development Study at age 50 to examine the attitudes that British 50 year olds have towards retirement, and in particular the concerns they might have about their future financial situation and whether they might be considering working beyond retirement age. By the age of 50 only a small minority (around 1 per cent) of study members had retired, but over the next 10 to 15 years a great many of them will be making the transition from work to retirement. The survey did not question study members about when they expected to retire, but the 2006 DWP ‘Attitudes to Pensions’ survey found that amongst those aged 45-55, 40% expected to be retired by the age of 60 and the English Longitudinal Study of Ageing found that in 2006 55% of those aged 60-64 were no longer working. In the UK at the turn of the century the average age retirement was 63 for men and 61 for women.
Keywords: NCDS8, 58 cohort, gender, retirement, pensions, savings, expectations.
Matt Brown and Brian Dodgeon analyse the results of four sets of cognitive assessments undertaken at age 50 by NCDS members (1958 birth cohort): word recall, delayed word recall, animal naming and letter cancellation. These are regressed onto the same cohort members’ cognitive test results at age 11 in the presence of other covariates to test the effect of health behaviours on age 50 cognitive ability by gender.
Keywords: NCDS8, 58 cohort, gender, health behaviours, smoking, drinking, memory, social class.