Overview of key data sources: Scottish Longitudinal Study

Organisation responsible: Longitudinal Studies Centre - Scotland.

Background and purpose: The Scottish Longitudinal Study (SLS) is a large-scale administrative data-linkage study. Data sources include census data, vital events data (births, deaths, marriages), National Health Service Central Register data (migration in or out of Scotland) and NHS data (cancer registrations and hospital episodes).

The SLS is a replica of the England and Wales Longitudinal Study (LS), with a few key differences. The LS began with data from the 1971 Census while the SLS began with data from the 1991 Census. The SLS is also based on a larger sample: 5.3% of the Scottish population compared to a 1% sample in England and Wales.

The SLS provides a high quality longitudinal research dataset, the largest of its kind in Scotland, which can be used to provide an insight into the health and social status of the Scottish population. Inclusion of demographic, socio-economic and health information allows the study of a range of social science and health questions such as geographic and social inequalities in health, ethnic health, occupational mortality and morbidity, fertility changes, social mobility and family reconstitution. It is envisaged that the data will be used for academic research, social policy and by government departments.

Study length: The study includes data from the 1991 and 2001 Censuses. Annual events information is included from 1991 onwards, with the exception of fertility events which go back to 1974.

Study content: 1991 and 2001 Census information (occupation, economic activity, housing, ethnicity, age, sex, marital status, health, education, religion etc), vital statistics (live births, stillbirths, infant mortality, deaths, widow(er)hoods, marriages) population data (immigration, emigration) health data (cancer registrations, hospital episodes).

Target population: Scottish population.

Sample size: Approximately 274,000 individuals, a 5.3% representative sample of the Scottish population drawn from the 1991 Census (sampling based on 20 birthdays).

Response rate: Not applicable (the census is compulsory; linkage and trace rates are high).

Method of data collection: Linked data from the Scottish Census and administrative records.

Smallest geographic unit reported: Local authority areas are the lowest spatial level on which data are given to users. While smaller area geographical identifiers are attached to SLS members, the scale at which analyses is allowed depends on the specific details of the proposed study. No analyses are allowed which could compromise the confidentiality of individuals in the SLS.

Availability of results and further information: The SLS is not a publicly accessible dataset available through any of the academic data archives. Potential users must apply for access. A team of researchers provides free support to academic researchers. As the data are highly confidential, researchers do not receive individual-level data directly, but can analyse data remotely, or in a safe-setting. For further information on accessing data, visit the Scottish Longitudinal Study webpage.