1. The ONS Longitudinal Study

2. © London School of Hygiene and Tropical Medicine The Office for National Statistics Longitudinal Study (LS) o What is it o What can you do with it? How to access the LS

3. © London School of Hygiene and Tropical Medicine The ONS Longitudinal Study Initial sample drawn from 1971 Census. Selected if birthday falls on one of four days in each year (‘LS birth dates’). Approximately 1% sample of population of England and Wales extracted. Data for the whole household available for each sample member. Maintained through addition of immigrations and new births with LS birth dates. Individuals linked from one census to another Data from censuses and vital registration systems. Losses to sample through deaths and out-migrations (though all records are retained in the database).

4. © London School of Hygiene and Tropical Medicine 2001 540,000 1991 543,000 1981 536,000 1971 530,000 Immigrations 173,593 New Births 271,676 Embarkations 39,796 Deaths 238,689 LS Sample: July 2010

5. © London School of Hygiene and Tropical Medicine

6. | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1971 1976 1981 1986 1991 1996 2001 2006 2011 Census Birth of Child Birth of Twins Census Death of Spouse CensusCancerDeath Person Included from 1971 Census Census © London School of Hygiene and Tropical Medicine

7. Types of study design using the ONS Longitudinal Study 1.Cross-sectional at each census (1971,1981,1991, 2001) 2.Longitudinal: investigating same people at 2+ Census points 3.Longitudinal: fertility, cancer incidence and mortality by Census characteristics before and after the event 4.Cross-sequential : comparing change in two cohorts (e.g. class mobility 1971 to 1991 with class mobility 1981 to 2001) 5.Inter-generational (parental characteristics of sample members in 1971 by their adult characteristics in a later Census)

8. © London School of Hygiene and Tropical Medicine Example Study: Longitudinal Analysis: Census Information + Events “Do teenage mothers suffer social disadvantage, either before or after their early motherhood?” Study population: Women aged 5 to 9 years at 1981, also present at 2001, using ‘live birth to sample mother’ records to identify first birth. (N=13,408)

9. CeLSIUS Downloadable tables: “Teenage Mothers” www.celsius.lshtm.ac.uk/download/wt080300.html

10. Potential Projects: Trends and variations in living arrangements of young people. “Are people in their 20s still living with their parents in 2001?” –Are living arrangements influenced by: Region, Ethnicity, Social class, Education, Household size/composition. Longitudinal follow-up on the mortality of caregivers “Do those caring for others in 2001 have higher or lower mortality than non-carers?” –Does mortality vary by: widow(er)hood status, intensity of caring (e.g. hours per week), general health prior to caring, household size or composition? © London School of Hygiene and Tropical Medicine

11. Potential Projects: Longitudinal analysis of the mortality of religious people. “Do mortality risks vary between people who expressed a religion in 2001 compared to those who were non-religious? –Potential confounders might include: Household composition, social class, ethnicity, education. Longitudinal analysis of the mortality of ‘retirement migrants’. “Do people who relocate after retirement have different mortality risks compared to those who stay in their usual place residence?” –Possible confounders might include: distance of migration, destination, marital status, family size/number of children, social class, education. © London School of Hygiene and Tropical Medicine

12. How to use the LS: conditions imposed by the need for confidentiality Projects are scrutinised by a Board before approval. Each member of project team must be awarded Approved Researcher status specifically for that project. Data are held in secure setting and cannot be downloaded. LS users can visit a secure setting (Angel/Pimlico, London) to analyse data directly. - or send code (e.g. in STATA or SPSS) which will be run for them. Individual-level data cannot leave the secure setting – instead, tables, models or aggregated datasets are released. Outputs are scrutinised for the disclosure of personal information (can limit detail of ethnicity, small-area geography and occupation). Publications and outputs need clearance.

13. © London School of Hygiene and Tropical Medicine Centre for Longitudinal Study Information and User Support (CeLSIUS) Free service to UK academic users. Interface between researchers and confidential LS database held by ONS. Assistance with drawing up research design and obtaining approvals. Specialist Research Support staff prepare data, tables or models to your specification (repeatedly!). Advice and support throughout your project.

14. © London School of Hygiene and Tropical Medicine On-line CeLSIUS resources at www.celsius.census.ac.uk Step-by-step guide to using the LS Interactive training modules Data dictionary Downloadable datasets (with limited number of variables/values) Downloadable tables (mini-research studies) Searchable publications database List of current/recent projects Links to other documentation and information

15. CeLSIUS: Centre for Longitudinal Study Information and User Support celsius@lshtm.ac.uk Professor Emily Grundy, Professor Pat Doyle, Lynda Clarke, Christopher Marshall, Neil Smith, Rachel Stuchbury