Institute of Epidemiology & Health Care



We enable research using the Office for National Statistics (ONS) Longitudinal Study - the largest nationally representative longitudinal dataset in the UK

Longitudinal studies follow the lives of individuals over a long period of time, showing us how people are affected by changes in society. The ONS Longitudinal Study (LS) contains the census data and some life events data of approximately one million sample members, collected over 40 years. CeLSIUS is funded by the ESRC to provide free support to researchers wishing to use this data.

About the ONS Longitudinal Study

About the ONS LS

Find out more about the study

About the ONS Longitudinal Study

Using the ONS LS

Find out how to access and use the data

Data dictionary

Data dictionary

Look up the variables in the study

Celsius Resources


Information and guidance to help you use the data

Research at Celsius


Current and past ONS LS research projects and the resulting outputs

About Celsius


Meet the team

Wordpress dashboard

Linking our Lives Blog

Our blog showcases outstanding research using the ONS LS


Linking our Lives Podcast

In conversation with researchers and users of ONS LS research


Research and policy briefs

Policy and research briefing notes on research using the ONS LS

News and events


Update from ONS on timescale of availability of 2021 LS data

The ONS previously reported that they were aiming for the updated LS research database to be available in the second half of 2024, dependent on data processing running smoothly. Unfortunately, this has not been the case and due to processing and resource issues they are having to delay the release of the 2021 LS research database until early Summer 2025. ONS apologises for any inconvenience this delay will cause and appreciates this is a significant change to the dates from those initially advertised.


Important update about the transition from the SRS to the IDS

Please see this 27 March 2024 message from ONS.


More news and events



Celsius Logo