A step-by-step guide to using the LS

1. Formulate your research question

What are you studying? Who will your sample be? What period would your research cover?

2. Is the LS the best data source for your research?

If you haven't already read about the ONS Longitudinal Study, you should do so. You should also consult the census forms if you are planning to use LS census variables:

  • Were the questions you are interested in asked in the years you want to study?
  • Were they asked of the age group you want to study?
  • If the responses were in pre-coded categories, will these categories meet the needs of your study?

You could also use CeLSIUS' data dictionary to check the categories in the variables you hope to use. Also, CALLS-Hub have a data dictionary that crosses all UK LS'. 

If you have any doubts about the suitability of the LS for your research contact us. If the LS is not for you, we might be able to suggest alternative sources of data. 

You should also review existing work on your subject that has used LS data, by looking at current and past projects as well as at our list of research outputs.

3. Study our online training

We have developed ten online training modules on: 

  • Analysing LS data (includes Poisson modelling and relative survival)
  • Defining a study population
  • Ethnicity
  • Events (includes births, deaths, cancer registrations and widow(er)hoods)
  • Fertility rates
  • Geography
  • Households and families
  • LS outputs
  • Mortality
  • Socio-economic status

These modules provide information on the variables available, suitable research designs and also give indicators of sample sizes. You can get further ideas by looking at our downloadable tables.

4. Contact CeLSIUS

Unless you are based outside the UK or in the private sector, you should be eligible for support from CeLSIUS (the service is free to the user, being funded by the Economic and Social Research Council). You should contact us - we will discuss your research question and your timescale, and pass your request on to a Support Officer who will guide you through the subsequent processes and make sure you get the best data for your research question. If you require one or two straightforward tables from the LS, either to establish whether the LS is likely to be useful, or to provide some background information, we can arrange this with a minimum of formality. 

If you are based outside the UK or in the private sector, please contact the LS team at the Office for National Statistics (ONS) directly.

5. About the application forms

There are three forms to complete. At the present time we estimate that from submission of your application to CeLSIUS to full and final approval (which must be given before any data can be released) you should allow from 6 to 8 weeks. This document explains the LS application and approvals process.

Form What is this form for?

ONE form for each project:

This is where you describe yourself and your project. If you are a BSc or MSc  student, your supervisor will be the lead researcher.

Supplement Part B asks for more detail about the data you wish to use; it is usually completed in collaboration with your Support Officer.

ONE form for each named person on the project:

A requirement to establish that the researcher is a 'fit and proper person' under the terms of the Statistics and Registration Act 2007. (An electronic image of the signature is acceptable).

  • SyOPs & Researcher Data Access Agreement form - this form is sent out by ONS' VML Service Desk upon receipt and approval of the above two forms

ONE form for each named person on the project:

Signed by each person on the project, to accept the conditions under which LS data can be accessed and used. (An electronic image of the signature is acceptable).

NOTE: Forms are usually completed and submitted electronically, though paper submission is also acceptable. However, do not submit any forms as read-only or PDF as the Administrative Officer will remove unnecessary extra pages before submitting them.  

6. Starting the application process

We recommend that you begin by completing as much as you can of the CRF and emailing it to CeLSIUS. You will be allocated a Support Officer who will help you with the rest of the application. You should also send us draft Approved Researcher forms at an early stage as these usually take longer to be approved than the CRF.  

You should use CeLSIUS' data dictionary to specify the variables that you want to include – these can be changed later but it is helpful both to you and to those considering your project to draw up an initial list at this stage. The  Support Officer will assist you with this. Once the CRF is completed, CeLSIUS will submit it to the LS Research Board at ONS.

Once the LS Research Board has approved the project your Support Officer can start work on it but cannot release any data until the final approval is given by the ONS Microdata Release Panel.

NOTE: The ONS Microdata Release Panel can only consider projects recommended by the LS Research Board once they also hold the completed and signed Data Access Agreement and have had confirmation that all named members of the research team have been given Approved Researcher status.

7. Applications for Approved Researcher status

Every researcher who is named in the CRF must gain Approved Researcher (Word) status: the aim is to establish that there is a public benefit in allowing this person access to sensitive data and that evidence exists that s/he will know how to deal with it and will do so responsibly. A separate application must be made for each new project, even if the researcher is already an Approved Researcher on another project. Approved Researcher is a legal status and the application form will be considered as a legal document in its own right. When completing it, provide specific information on your experience and research record (including technical experience of microdata analysis) and do not assume any prior knowledge on the part of the reader. You can see the criteria used to assess the application in the guidance notes that preface the main form.

Only people who have Approved Researcher status on your project can be shown Intermediate Outputs (see below).

8. Attend a Safe Researcher certification course

While you are awaiting approval of your project, arrange to attend a one-day (10 am till 4 pm) training course if possible. Contact us for advice on forthcoming dates. Attendance at this course is a requirement if you are planning to visit a VML lab (see next section) and is optional but useful for others.

9. Perform analyses

Your Support Officer will construct the dataset for your research (and amend it if necessary as your study proceeds). The dataset will be held in a secure system which can only be accessed from the Virtual Microdata Laboratory (VML) areas in ONS offices; these are situated in London (Pimlico), Hampshire (Titchfield) and Wales (Newport). 

One way of analysing your data is to send code (e.g. in STATA, SPSS or SAS) to be run in your absence, or discuss with your Support Officer the outputs that you require (perhaps constructing specimen tables or models) and s/he will write and run code for you. Another option is to visit a VML lab yourself and analyse your own data. Please always try to book a lab visit in advance in case the VML is not available.

A further possibility is to specify an aggregated dataset (which will have a limited number of values) to be released for you to analyse at your place of study/work; see dataset on survival for an example. Individual-level datasets will never be released.

10. Receive Intermediate Outputs from CeLSIUS

When you want research outputs to leave the secure system in the VML, perhaps to work on them on your own computer or to show them to other Approved Researchers on the same project, they will be referred to as Intermediate Outputs. To maintain the security of the LS all Intermediate Outputs are checked by a Support Officer and encrypted before being emailed to users. 

Intermediate Outputs must be stored at a secure location (which you will have specified on the Customer Request Form at questions B3 and B4) and can only be shown to Approved Researchers on the same project.  

11. Seek Final Output Clearance for results to be made public

When you want to disseminate your LS results beyond your project team you must obtain Final Output Clearance from the LS Research Board.

The process for clearing final outputs reduces the risk of disclosure and ensures that the LS is properly described. Key criteria include:

  • Results aggregated to a minimum cell threshold. ONS asks that in results from which a count of individual persons could possibly be calculated - e.g. percentages, or graphs based on percentages - that count is 10 or more. However, ONS may consider giving clearance to results which do not meet this criterion, if there is a scientific justification.
  • The LS is described correctly. Standard descriptions are available.
  • 'Source: ONS Longitudinal Study' is added to tables and figures, where appropriate.
  • Results appreciate that the LS includes data for England and Wales only.

Final outputs may be either reports, journal articles, presentations or abstracts, or simply a set of results which are destined to be worked up as any of these. Allow 5 working days for final outputs clearance although many outputs are cleared more quickly than this. Complete a Final Output Clearance Form (Word) and send it with a copy of your work to us.

Once your final output has been cleared for public release you may disseminate it a number of times without resubmitting it for clearance, as long as no new results are included. Your cleared Final Outputs are given a clearance number which you should cite in your publications. You are asked to acknowledge the support of CeLSIUS and ONS in your publications and include a disclaimer. We have a suggestion below:

"The permission of the Office for National Statistics to use the Longitudinal Study is gratefully acknowledged, as is the help provided by staff of the Centre for Longitudinal Study Information & User Support (CeLSIUS). CeLSIUS is supported by the ESRC Census of Population Programme under project ES/K000365/1. The authors alone are responsible for the interpretation of the data."

We also ask researchers to note that all statistical results remain Crown Copyright, and should be acknowledged either as such and/or as "Source: ONS". 

The following copyright statement should be featured along with the above acknowledgement:

"This work contains statistical data from ONS which is Crown Copyright. The use of the ONS statistical data in this work does not imply the endorsement of the ONS in relation to the interpretation or analysis of the statistical data. This work uses research datasets which may not exactly reproduce National Statistics aggregates".

If you need to cite ethical approval for the ONS LS itself, you should refer to PIAG and NIGB.

12. Delete all Intermediate Outputs

When your project is complete you should delete all Intermediate Outputs from your computer.

Page last modified on 24 jan 14 13:08 by Rachel Stuchbury