The Scottish Longitudinal Study

What is the Scottish Longitudinal Study?
What can the SLS tell you?
How can the SLS be used?
What resources are available?
Further reading

What is the Scottish Longitudinal Study?

The Scottish Longitudinal Study (SLS) is a large-scale linkage study which has been created by using data available from current Scottish administrative and statistical sources. These include census data, vital events data (births, deaths, and marriages), National Health Service Central Register (NHSCR) data (migration in or out of Scotland) and National Health Service (NHS) data (cancer registrations and hospital admissions). The SLS is similar to the Office for National Statistics Longitudinal Study of England and Wales (ONS LS), but there are some key differences. The SLS is a 5.3% representative sample of the Scottish population, based on 20 birthdays, rather than a one per cent sample, based on four birthdays, as in the ONS LS. The SLS began with data from the 1991 census, while the ONS LS began with data from the 1971 census. There are a small number of variables that are included in the ONS LS which are not included in the SLS and vice versa. Most notably, hospital admissions data can be linked into the SLS – similar data are not included in the ONS LS. Approximately 274,000 SLS members have been identified from the 1991 census and information for these individuals have been linked from other datasets, including the 2001 census, vital events and health information. The Longitudinal Studies Centre – Scotland (LSCS) based in the University of St Andrews and the office of the General Register Office for Scotland (GROS) in Edinburgh is responsible for the establishment and maintenance of the SLS. The LSCS team also support users who wish to undertake projects with the SLS data.

What can the SLS tell you?

As the SLS includes a range of variables which can be explored, including cultural, demographic, economic, health, housing and social issues, its potential uses are considerable.

Firstly, social differentials in health and mortality can be explored using such measures as the Registrar General's social class, deprivation indices, National Statistics Socio-Economic Classification (NS-SEC), occupation and industry, housing tenure, car access, overcrowding and lack of amenities in housing, ethnicity, religion and sex. The effects of geography and migration can also be examined.

Other fields of study are fertility, labour participation, occupational mobility and housing.

Because data are not only collected on the sample members but also on their household members, the SLS is also very useful for studying change in household and family formation and dissolution.

Change over time can be looked at because of the linkage of data from more than one census. This enables the study of how an event or situation of interest at one point in life (such as mortality risk) is affected by circumstances earlier in life (such as social class). In particular the integration of hospital admissions data makes the SLS a unique resource in the UK, unparalleled in most of the developed world.

The England and Wales LS, upon which this dataset is modelled, has been used to look at a range of important questions including: occupational mortality, fertility changes, family reconstitution, women’s occupations, geographical and social inequalities in health, social mobility and ethnic health. Much of the work done using this database in England and Wales has fed into government social policy, particularly into the health targets being put forward by the Department of Health. It is envisaged that the SLS will be used in much the same way in Scotland. In addition, the SLS has been designed to be compatible with the England and Wales LS so that an integrated British LS is a realistic possibility in the future (four of the 20 birthdays match those used in the England and Wales LS). At the very least, it will be possible for researchers to select similar datasets from the LS and SLS to allow comparisons to be made throughout Britain.

How can the SLS be used?

Because of the sensitive nature of the data held in the SLS, it is not a publicly accessible dataset available through any of the academic data archives. The dataset is held at the GROS site in Edinburgh. The LSCS team extract the data for users in the form of aggregated tables, which are designed to protect the confidentiality of SLS members. Where the analysis requires it, researchers may be allowed access to anonymised individual-level data in the SLS ‘safe setting’ based in the GROS. A detailed description of the process of data access can be found at the LSCS web site. Anyone considering using the SLS should contact the SLS support team at the LSCS.

What resources are available?

The datasets currently linked in the SLS database are:


Census datasets:

1991 Census (data for SLS members and their households)
2001 Census (data for SLS members and their households)

New entry datasets:

Post Census 1991, then each year from 1992 onwards
New births into the sample
Immigrants into the sample

Vital events datasets:

Post Census 1991, then each year from 1992 onwards
Births to sample mothers and sample fathers
Stillbirths to sample mothers and sample fathers
Infant mortality of children of sample mothers and sample fathers
Marriages of sample members (SLS brides and grooms)
Deaths of sample members

Widow(er)hoods of sample members
Emigration out of Scotland of SLS members
Re-entries into Scotland after previous emigrations of SLS members

Health events datasets:

Cancer registrations for sample members
Hospital admissions and discharges for sample members
Health events data are linked as required for approved research studies and are not held as part of the SLS database. The SLS data dictionary, available on the LSCS web site, explains the detail of the SLS variables held on the SLS databases.

Further reading

The working papers published on the LSCS web site include detailed information about how the SLS was created and linked and how it may be accessed.