NCDS Age 23 Sweep

Sweep details

Dates August 1981 to March 1982
Age 23
Achieved sample 12,537 (cohort members)
Respondents Cohort members
Fieldwork agency NOP Market Research Limited and Social and Community Planning Research
Survey mode Face to face
Data access

Main dataset available via the UK Data Service [SN 5566]. Visit the UK Data Service website to access the data.


The age 23 sweep was the first to not involve the parents of the cohort. The cohort had reached a stage in their life marked by major transitions – for example, from school or full-time further and higher education to work, from dependent status in their families of origin to independent status as members or heads of new households, from single status to partnership with marriage partners or cohabitees, or from childlessness to parenthood.

During a 90 minute interview, information was collected about jobs, apprenticeships, training and any other education since 16, family life, household composition, housing, relationships, children, physical and mental health, smoking, drinking, religion, leisure activities and voting.

Special features at age 23


The age 23 sweep sought to collect a comprehensive measure of family income. Income has been measured in all subsequent major sweeps, allowing for the study of income mobility and the inter-relationship between income and other aspects of life.

Linked examinations records, and qualifications

Examination results were obtained in 1978, by writing to the schools which cohort members were attending at the time of the age 16 survey in 1974.

Schools were also asked if cohort members had gone to study elsewhere after leaving school, and if so the relevant institutions were contacted and later examination results obtained.

The age 23 sweep, and all subsequent sweeps have continually collected information about further qualifications obtained throughout life, meaning that NCDS can be used for detailed study of the factors associated with differing levels of educational success and the impact that qualifications have on later experiences and circumstances.


Measuring mental health and depression has long been a key focus of NCDS. The principle measure of depression in adult life has been the ‘Malaise’ scale which was first included in the age 23 sweep.

This scale has been featured in almost every sweep ever since, making NCDS an invaluable resource for examining factors associated with different trajectories of mental health and the impact that depression has on other aspects of life.

The malaise scale has also been included in BCS70 since cohort members were 16, providing opportunities for cross-cohort comparisons.


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

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 23 Guide to the Dataset

User Guide for the 4th sweep of NCDS

Date published: 01/05/1981
PDF: 7,71 MB


NCDS 2006 Re-deposit User Guide

User guide to accompany the redeposit of data up to age 46

Date published: 01/11/2006
PDF: 87,19 KB


NCDS Age 23 Derived Variables

Derived variables for sweep 4 of NCDS

Date published: 06/05/2000
PDF: 267,28 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 23 Annotated Questionnaire Documentation

Annotated version of the questionnaire administered in the 4th sweep of NCDS

Date published: 01/05/1981
PDF: 5,08 MB

Technical reports

NCDS Age 23 Survey Methodology (with Appendices)

Survey Report for NCDS4 with appendices

Date published: 01/10/1982
PDF: 7,26 MB

Data notes

No material of this type is available.


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 Age 23 Open Coded Data

Note on open coded data in NCDS sweep 4

Date published: 01/05/1981
PDF: 4,81 MB


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