Scottish Longitudinal Study
Development & Support Unit
Why was the SLS set up?
The SLS was created in response to the relative lack of longitudinal datasets in Scotland compared to England, and provides a high quality longitudinal research dataset that can be used to provide an insight into the health and social status of the Scottish population and how this changes over time.
Longitudinal studies have a long history in British social and epidemiological research, though the majority are based on surveys or panel studies. Some studies, such as the British Household Panel Study (BHPS) use sampling with replacement, but most do not. Because all such studies rely on re-interviews of the same people over time, a high proportion of study members become lost at follow-up. The SLS has been set up to collect data that is either required by law (Census, vital events registration) or is a standard administrative function (NHS patient records). As a result attrition rates are extremely low and linkage rates for events tends to be very high. The sample size (approx. 5% of population) is very large compared to most surveys and panel studies.
The existence of a longitudinal study for Scotland is important, as the region differs from the rest of the UK in numerous ways. For example, compared to the rest of the UK Scotland has:
- higher overall mortality rates (commonly known as the ‘Scottish Effect’);
- higher rates of mortality for specific causes such as lung cancer and heart disease (Scotland ranks amongst the worst in Europe for these);
- lower fertility rates;
- significant issues due to population ageing; and
- higher rates of household deprivation.