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 contains the census data and some life events data of approximately one million sample members, collected over 40 years. This service is free to the user.

About the ONS Longitudinal Study

About the ONS Longitudinal Study

Find out more about the study

About the ONS Longitudinal Study

Using the ONS Longitudinal Study

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 LS projects and the outputs resulting from this research

About Celsius


Meet the team



ONS Longitudinal Study joins CLOSER

CeLSIUS is delighted to announce that the ONS Longitudinal Study is one of eleven studies to have joined CLOSER. We very much look forward to collaborating with CLOSER, which brings together world-leading longitudinal studies to maximise their use, value and impact and improve understanding of key social and biomedical challenges.


Guides to using ONS LS data

A new guide to mortality data - our final guide - is now available, along with guides to births and fertility data, defining a study population, ethnicity data, events data and socio-economic indicators.


CeLSIUS funding to 2025

We are delighted to announce that we have secured funding from ESRC to continue to support the ONS Longitudinal Study until 30 September 2025. We are currently supporting users remotely - please see below. We look forward to continuing our work with our current LS users, and to welcoming many new researchers - please get in touch via celsius@ucl.ac.uk for more information.


SRS and CeLSIUS response to COVID-19

The ONS SRS Safe Settings and UCL offices were closed in March, in accordance with government guidelines, and will remain closed until further notice. CeLSIUS is able to offer remote user support for ONS LS projects - please contact us via celsius@ucl.ac.uk.

LS project support will be prioritised in the following order:

1) of immediate government interest – e.g. covid-19
2) examined work nearing deadline (before July 31st 2020)
3) work only using the LS nearing study period end (before July 31st 2020)
4) work using the LS nearing study period end (before July 31st 2020)
5) ongoing work only using the LS
6) new work only using the LS 
7) other work
Please note:
We will still accept and process new applications to use the LS but we estimate that, from application submission to final approval, you should allow a minimum of eight weeks. Also, support for these once they are approved will be limited for the time being.
Large scale cross tabs and other work involving extensive manipulation to prevent disclosure will not be cleared. 

New x-file (restricted variables) requests may be submitted, but ONS can only review them and cannot prepare/provide access to them. If you have already been given access to an x-file dataset, however, you will still be able to access it.

Additionally, approved researchers can apply to access their existing projects from home subject to guidelines set out by ONS on accessing secure research data as an accredited researcher.

Thank you for your patience while this remote service is in place.



New CeLSIUS paper

Are ‘healthy cohorts’ real-world relevant? Comparing the National Child Development Study (NCDS) with the ONS Longitudinal Study (LS) (Authors: Gemma Archer, Wei Xun, Rachel Stuchbury, Owen Nicholas & Nicola Shelton) is now out on fast track release  https://doi.org/10.1332/175795920X15786630201754


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