NCDS Age 50 Sweep

Sweep details

Dates August 2008 - April 2009
Age 50-51
Achieved sample 9790 (cohort members)
Respondents Cohort members
Fieldwork agency NatCen Social Research
Survey mode Face to face plus paper self-completion
Data access

Main dataset available via the UK Data Service [SN 6137]. Visit the UK Data Service website to access the data.


The age 50 sweep comprised a 60 minute CAPI interview (which included a series of memory and concentration tasks and a 10 minute self-completion section), and a 16-page self-completion questionnaire which was mailed to all cohort members before their interview.

The main topics covered in the interview were: household composition, housing, relationships, pregnancies, children and wider family, employment and income, education and training, use of computers, physical and mental health, smoking and drinking, exercise, height and weight, social participation and voting. The interview also included four cognitive assessments measuring memory, verbal fluency and concentration.

The main topics covered in the paper self-completion questionnaire were: leisure activities, personality, sleep, values, attitudes and well-being. An open question at the end asked respondents to describe their imagined lives at 60.

Cohort members (and their partners) were also asked for permission to link their survey responses with health records held by the NHS and economic records held by the Department of Work and Pensions (DWP) and Her Majesty’s Revenue and Customs (HMRC).

Special features at age 50


The age 50 survey included a module comprised of a series of cognitive assessments which sought to measure memory, verbal fluency, perception and attention at age 50.

These assessments were the first cognitive assessments conducted since cohort members were age 16; meaning that for the first time since adolescence analyses can be performed which use cognitive function as an outcome variable rather than a predictor.

The rich information which has been collected over the life-time of the study allows the determinants of cognitive ability at age 50 to be examined. For example, researchers are able to investigate the impact of a full range of life-time health behaviours such as exercise, diet, smoking and alcohol consumption, all of which are potentially modifiable at the individual level. Understanding the impact of these behaviours on cognitive function is vital if levels of dementia in the general population are to be reduced in the future.

Data Linkage

Cohort members were asked for consent to link their survey data with health and economic information held by the NHS, DWP and HMRC.

Co-resident partners were also asked for consent to health and economic data linkage.

Combining information from these records with the survey data collected over the years will provide a much fuller picture of the health and economic circumstances of cohort members.


The paper self-completion questionnaire included a 50 item personality inventory which measured the so-called ‘Big-5’ personality traits (extraversion, agreeableness, conscientiousness, agreeableness and intellect).

These personality traits are generally considered to be relatively stable and reliable indicators of how individuals differ in response to particular situations. A significant number of publications have already examined links between personality and other issues ranging from obesity to voter turn-out but many more questions can be researched using these measures.

Imagine you are 60

On the final page of the paper self-completion questionnaire respondents were asked to imagine the lives they would be living at 60 and to write a few lines describing their interests, home life, health, well-being and work at this time.

This paralleled a question asked in the age 11 sweep when cohort members had been asked to write about their imagined life at age 25.

Anonymised transcripts of the ‘Imagine you are 60’ responses are available from the UK Data Service. The responses collected provide a fascinating insight into the differing ways in which NCDS cohort members felt about their future.

The next NCDS sweep will take place at 62, so it will be possible to compare these projections with actual circumstances.


  • User guides
  • Questionnaires
  • Technical reports
  • Data notes
  • Additional
User guides

NCDS Age 50 Guide to the Dataset

Final version of the dataset userguide for NCDS age 50 sweep

Date published: 01/10/2012
PDF: 865,42 KB


NCDS Hospital Episode Statistics (HES) User Guide

This guide describes the data linkage of health administrative records from the Hospital Episode Statistics (HES) to survey data for cohort members in the National Child Development Study (NCDS).

Date published: 08/02/2021
PDF: 166,98 KB


Handling missing data in the National Child Development Study – User Guide

This user guide aims to describe and illustrate a straightforward approach to missing data handling, while detailing some more general considerations around missing data along the way.

Date published: 12/07/2021
PDF: 657,33 KB


NCDS Age 50 ‘Imagine You Are 60…’ User Guide

This document has been prepared to accompany the deposit, with the UK Data Archive at the University of Essex, of a data set of textual responses to an open ended question asked as part of the 2008/9 follow-up of NCDS.

Date published: 01/06/2012
PDF: 501,83 KB


NCDS Birth-Age 55 Response and Deaths Dataset User Guide

This document accompanies the deposit of the NCDS Response and Deaths dataset at the UK Data Service in March 2015.

Date published: 01/03/2015
PDF: 647,55 KB


NCDS Age 23-50 Partnership Histories

A guide to the partnership histories dataset collected from age 23 onwards

Date published: 01/11/2011
PDF: 245,98 KB


NCDS revised region variables

Date published: 01/03/2012
PDF: 523,56 KB


Partnership Histories Guide (1974-2013)

Date published: 01/11/2017
PDF: 374,82 KB


Activity Histories Guide (1974-2013)

Date published: 01/10/2016
PDF: 594,01 KB


NCDS Age 50 Questionnaire Documentation

Paper representation of CAPI and CASI interviews

Date published: 01/10/2009
PDF: 1,4 MB


NCDS Age 50 Self-Completion Questionnaire Documentation

Questionnaire given to cohort members for the Age 50 sweep of NCDS.

Date published: 01/05/2008
PDF: 751,45 KB


NCDS Age 50 Summary Of Questionnaire Content

Summary of questionnaire content for the age 50 sweep of NCDS.

Date published: 22/07/2008
PDF: 37,79 KB

Technical reports

NCDS Age 50 Technical Report

Technical Report for NCDS Sweep 8 conducted at age 50

Date published: 01/04/2010
PDF: 1,05 MB


NCDS Age 50 Technical Report Appendices

Appendices to accompany the technical report for NCDS age 50 survey

Date published: 01/10/2009
PDF: 9,51 MB


Evaluation of paper self-completion questionnaire planned for NCDS age 50 sweep

Technical report to evaluate the usefulness of a supplementary paper self-completion questionnaire as a data collection instrument.

Date published: 01/07/2008
PDF: 381,38 KB

Data notes

NCDS Age 50 Paper Self Completion – Response rates and response bias

The aim of this brief descriptive paper is to provide information on response to the paper self-completion questionnaire that formed part of the data collection for the eighth sweep of the 1958 British birth cohort study

Date published: 02/12/2011
PDF: 146,72 KB


Deriving highest qualification in NCDS and BCS70

This Data Note explains the derivation of variables on Highest Educational Qualification obtained by cohort members in the National Child Development Study (NCDS) and the 1970 British Cohort Study (BCS70).

Date published: 01/01/2011
PDF: 514,11 KB


NCDS Birth-Age 50 Target and Achieved Samples

Table of target and actual sweep samples for NCDS up to age 50

Date published: 01/05/2008
PDF: 21,84 KB


NCDS Ethical Review and Consent

Review of the ethical practices throughout NCDS

Date published: 02/06/2014
PDF: 1,76 MB

Contact us

Centre for Longitudinal Studies
UCL Social Research Institute

20 Bedford Way
London WC1H 0AL