The Scottish Longitudinal Study (SLS) is a large-scale linkage study created using data from administrative and statistical sources. These include: census data from 1991 onwards; vital events data (births, deaths, marriages); NHS Central Register data (gives information on migration into or out of Scotland); and education data (including Schools Census and SQA data). More detail can be found in our Guides and Resources section.

The SLS is a replica of the ONS Longitudinal Study (ONS LS), which has now been running for over 40 years. The ONS LS was designed as a 1% sample of the population of England and Wales. Initial data were extracted for a sample of the 1971 census, and then linked to administrative, vital events and health datasets through time. Although Scotland was originally included in the ONS LS, it was removed at an early stage because of the very small size of the Scottish sample.

The SLS is a 5.3% sample of the Scottish population and begins from the 1991 census.