NCDS Age 55 Sweep

Sweep details

Dates September 2013 - March 2014
Age 55
Achieved sample 9137 (cohort members)
Respondents Cohort members
Fieldwork agency TNS-BMRB
Survey mode Sequential mixed mode using web and telephone
Data access

Main dataset available via the UK Data Service [SN 7669]. Visit the UK Data Service website to access the data.


The age 55 survey ran from September 2013-March 2014. Data collection involved a sequential mixed mode approach whereby cohort members were invited to complete a web survey and those not responding were invited to participate via telephone.

The main topics included in the 25 minute questionnaire were household composition, relationships, children, grandchildren, caring responsibilities, housing and housing wealth, employment, income, retirement expectations, health and leisure activities.

Special features at age 55

Mixed mode data collection

The age 55 sweep used a sequential mixed mode approach whereby cohort members were invited to first complete a web survey and those not responding were invited to participate via telephone.

Amongst the UK birth cohort studies this was both the first use of a web survey and the first use of a mixed mode approach to data collection. 9,137 cohort members took part in total, with 66 per cent doing so online.

The study included a small experiment, whereby a randomised subset of study members were allocated to a single mode, telephone-only interview, in order to test for the presence of mode effects on participation and measurement.


Study members were asked about caring responsibilities they had for their parents and their grandchildren.

A significant proportion also have children living at home meaning that many find themselves ‘sandwiched’ between caring for both older and younger generations. Participants were asked about the nature of their caring responsibilities and the amount of time they spent caring.

Researchers can use this information to answer important questions about the impact of caring on the cohort members, for instance on health and well-being, or decisions related to labour market participation.

Employment , housing and partnership histories

The age 55 sweep made use of an interactive visual calendar which sought to aid cohort members with the completion of three ‘event history’ sections.

Cohort members were asked to give details of their cohabiting relationships, housing circumstances and periods of economic activity since the time they were last interviewed. The calendar aimed to assist with recall of past events by simultaneously displaying transitions across these three domains of life.

Retirement expectations

At age 55 a new set of questions asked respondents to report the likelihood of being in work at 60 and 66 (state pension age).

Researchers can use responses to these questions, in conjunction with the longitudinal information collected about employment and income over time to examine how retirement expectations are influenced by lifetime experiences of work and poverty.

Retiring by 55 was fairly rare, but as NCDS continues it will become an increasingly valuable resource for studying the factors associated with both continuation and exits from the labour market in older age and the impact this has on other aspects of life.

Health, disability and well-being

Health and well-being was a key focus of the age 55 sweep. Cohort members were asked to subjectively rate their health and to report any specific health conditions they suffered from.

Well-being was measured using a 6 item version of the CASP scale. ONS harmonised measures of long-standing illness and disability were also included.


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

NCDS Age 55 Survey User Guide

User Guide for the 2013 follow-up to NCDS when participants were age 55

Date published: 01/02/2015
PDF: 550,35 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: 01/09/2022
PDF: 563,89 KB


Handling missing data in the CLS cohort studies – 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: 03/06/2024
PDF: 1000,62 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 55 Questionnaire Documentation

Paper representation of the CATI and CAWI interviews conducted for the age 55 sweep of NCDS

Date published: 01/05/2013

Technical reports

NCDS Age 55 Technical Report

Technical Report for the Age 55 sweep of NCDS

Date published: 01/05/2014
PDF: 868,6 KB

Data notes

Is there scope for harmonisation of the National Child Development Study and the English Longitudinal Study of Ageing?

This report explores the potential in harmonising elements of a prospective birth cohort study (NCDS) and a panel study of older people that includes a retrospective life history module (ELSA).

Date published: 01/07/2014
PDF: 983,55 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

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London WC1H 0AL


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