MCS Age 3 Sweep

Sweep details

Dates September 2003 to April 2005
Age 3
Achieved sample 15,808 (cohort members); 15,590 (families)
Respondents Cohort members, parents, older siblings (up to two aged between 10 and 15, England only)
Fieldwork agency NOP and Millward Brown Ulster
Survey mode Face-to-face
Data access

Main dataset available via the UK Data Service [SN 5350]. Visit the UK Data Service website to access the data.


The Age 3 Sweep examined the physical, social and cognitive development of cohort members, alongside family context and circumstances, and preschool experiences.

Interviewers visited the cohort member’s home and conducted face-to-face interviews with both parents. Parents also answered some questions via self-completion. Topics covered included family composition, housing and local area, parental education, employment and income, parental health, parenting activities and attitudes. Information was also collected about the cohort member’s health, behaviour, development, leisure activities and pre-school education and childcare.

The following cognitive assessments were conducted by the interviewer with the cohort member: Naming Vocabulary (British Ability Scales) and four subtests from the Bracken School Readiness Assessment (Colours, Letters, Sizes and Comparisons).

Interviewers measured the height and weight of cohort members.

Parents took oral fluid from the cohort member by swabbing the inside of their cheek with a foam swab, for the purpose of measuring exposure to common childhood infections.

In England, up to two older siblings (aged 10-15) of cohort members did a short self-completion questionnaire. This was included to provide data for the National Evaluation of the Children’s Fund. Topics covered included leisure and extra-curricular activities, life at home, health, school, bullying and victimisation, and anti-social behaviours.

The interviewer completed a questionnaire about the neighbourhood the family lived in and the home environment.

Special features at age 3

Cognitive assessments

It was the first time cohort members’ cognition was measured directly, using a battery of well-validated, age-appropriate assessments.

Physical measurements

It was the first time cohort members’ height and weight were measured.


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

MCS 9 Months-Age 11 Guide to the Datasets (Eighth Edition)

Eighth Edition of MCS User Guide to the Datasets

Date published: 01/02/2014
PDF: 934,04 KB


MCS Age 3 User Guide to Initial Findings

User guide to initial findings for the Age 3 sweep of MCS.

Date published: 01/07/2007
PDF: 2,54 MB


MCS Age 3 Guide to Derived Variables

User Guide to the derived variables for sweep 2 of MCS

Date published: 01/08/2012
PDF: 505,76 KB


MCS 9 Months-Age 11 Guide to psychological and developmental inventories

Guide to the psychological and developmental inventories in MCS, covering 9 months old to age 11.

Date published: 05/01/2015
PDF: 741,77 KB


MCS Age 3 CAPI Questionnaire Documentation (Version 1)

Paper representation of CAPI questionnaire for the Age 3 sweep of MCS

Date published: 01/03/2006
PDF: 1,13 MB


MCS Age 3 Older Siblings Questionnaire

Questionnaire given to older siblings of cohort members as part of the Age 3 sweep of MCS.

Date published: 01/05/2005
PDF: 41,7 KB


MCS Age 3 Neighbourhood Assessment Form

MCS sweep 2 Form about views on local area

Date published: 01/05/2004
PDF: 21,58 KB


MCS Age 3 CAPI Questionnaire Documentation: Child Measurements

Paper representation of CAPI questionnaire for child measurements

Date published: 01/05/2006
PDF: 127,86 KB

Technical reports

MCS Age 3 Fieldwork Technical Report

Technical report on the development and fieldwork of MCS2

Date published: 01/05/2003
PDF: 440,52 KB


MCS Age 3 Fieldwork Technical Report Appendices

Appendices to the technical report on the development and fieldwork of MCS2

Date published: 01/05/2003
PDF: 13,05 MB


MCS Age 3-7 Technical Report on Response (Third Edition)

Third edition of the MCS technical report on response rates including sweeps 2,3 and 4

Date published: 01/06/2010
PDF: 719,47 KB

Data notes

MCS Geographical Identifiers

Geographic Identifiers in MCS

Date published: 01/06/2009
PDF: 45,77 KB


MCS data note – Interpreting test scores at ages 3, 5 and 7

One particularly valuable element of MCS is the standardised tests undertaken by the cohort members to assess their cognitive skills and educational attainment. This data note gives an overview of the variables on performance in these tests at ages 3, 5 and 7.

Date published: 01/09/2013
PDF: 570,24 KB


MCS Age 3 The home learning environment

In an article published in 2008, Melhuish et al. investigated the influence of aspects of home environment upon literacy and numeracy achievement at school entry and at the end of the 3rd year of school. In their work, they created a “home learning environment index”

Date published: 01/07/2012
PDF: 211,17 KB


MCS Age 3 Derived Variables

This documentation describes all of the derived variables deposited on the Millennium Cohort Study Second Survey Datasets

Date published: 01/06/2006
PDF: 196,54 KB


MCS Ethical Review and Consent

This note reports on the approach adopted to ethical review and informed consent for the various stages of the Millennium Cohort Study.

Date published: 01/02/2019
PDF: 7,98 MB

Contact us

Centre for Longitudinal Studies
UCL Institute of Education

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