Here you will find all the documentation for our studies. This includes survey questionnaires, interviewer instructions, showcards, technical reports, survey reports, and derived variables. For more information, take a look at our guide to the different documentation types.
Showing 431 results.
User guides
Millennium Cohort Study Sweep 8 (Age 23) User Guide
The comprehensive guide to the data from the Age 23 Sweep of the Millennium Cohort Study, carried out in 2023-24 when participants were aged 23.
Date published: 10 February 2026
Questionnaires and interviewer instructions
Millennium Cohort Study Sweep 8 (Age 23) Household Grid And Proxy Questionnaire
MCS cohort members completed this questionnaire for the Age 23 Sweep.
Date published: 10 February 2026
Technical reports
Millennium Cohort Study Sweep 8 (Age 23) Technical Report
Technical report authored by Ipsos which provides all technical details regarding the design and implementation of the MCS Age 23 Sweep.
Date published: 10 February 2026
Technical reports
Millennium Cohort Study Sweep 8 (Age 23) Technical Report Appendices
Appendices accompanying the Technical Report authored by Ipsos which provides all technical details regarding the design and implementation of the MCS Age 23 Sweep.
Date published: 10 February 2026
User guides
1970 British Cohort Study: Partnership Histories, 1986-2021 User Guide
The purpose of the Partnership Histories dataset is to merge all data on live-in relationships in successive sweeps into one longitudinal dataset. For the fifth edition (January 2026), the data has been updated to include partner data collected at sweep 11 (2021, Age 51) and includes partner information up to the date of interview between 2021 and 2024.
Date published: 14 January 2026
User guides
1970 British Cohort Study: Activity Histories, 1986-2021 User Guide
The purpose of the BCS70 activity histories dataset is the merge of all data on work and non-work activities, in the successive sweeps, into one longitudinal dataset. For the fifth edition (January 2026), the data has been updated to include reported activities from sweep 11 (2021, Age 51) with employment histories up to sweep interview date between 2021 and 2024.
Date published: 14 January 2026
User guides
MCS Age 14 Sweep time use diary user guide
This user guide provides an introduction to the fully harmonised time use diary data collected during the Age 14 Sweep of the Millennium Cohort Study.
Date published: 28 October 2025
User guides
Next Steps 2019 Web Survey User Guide
This user guide provides information about the data arising from the Next Steps 2019 Web Survey.
Date published: 23 October 2025
Questionnaires and interviewer instructions
Next Steps 2019 Web Survey Questionnaire
This questionnaire pertains to the Next Steps 2019 Web Survey.
Date published: 23 October 2025
User guides
UK Early Life Cohort Feasibility Study: Age 9-10 months sweep User guide
The comprehensive guide to the data from the UK Early Life Cohort Feasibility Study: Age 9-10 months sweep.
Date published: 3 October 2025
Centre for Longitudinal Studies
UCL Social Research Institute
20 Bedford Way
London WC1H 0AL
Email: clsdata@ucl.ac.uk
