The Welsh Health Survey informs local government, NHS, and nationwide health strategy.

The Welsh Health Survey (WHS) collects information on the health and health-related lifestyles of people living in Wales. It is a major source of information about the health of people in Wales, the way the NHS is used, and behaviours that can affect health, such as smoking and alcohol consumption.

Data for the WHS is collected via face-to-face-interviews and self-completion questionnaires. The sampling unit for the WHS are households, however all adults within households were asked to take part. Families with children under the age of 16 are eligible, however where the household has 3 or more children, up to two children between the ages of 0 and 15 are randomly selected for inclusion in the study. Interviews are used to collect data at the household level, with questionnaires distributed to household members. Information on the household type and employment status of the household reference person are collected, and the interviewer is asked to comment on the condition of the property. Separate self-completion questionnaires are used to collect data for adults and young people (aged 13-15), whilst adults/guardians are required to complete questionnaires on behalf of children younger than 13 years old.

The WHS data provided to SAIL relates to survey years 2011, 2013 and 2014 covering only adults - aged 16 and older - who have consented to allow their data to be linked, with consent to data link data being included on a trial basis for 2011. As a result WHS data in SAIL can be analysed only at the individual adult level (and with a very limited number of records for 2011). By contrast WHS data in the UK Data Archive allows for adult-child records to be combined for research exploring ‘household’ health or the links between parental and child health, for example.

Derived variables are those which have been created as an additional value based on responses to other variables, primarily for facilitate further analysis.

Please note: From April 2016 health and health-related lifestyles are reported in in SAIL by the National Survey for Wales Dataset.