Methodology

The HLS used a sub-sample of the National Health Survey 2017-18, and data from the HLS was combined with that of the National Health Survey. As such information related to survey scope, coverage, data collection, input coding and data quality issues are addressed elsewhere in the Users Guide.

Specific issues pertaining to the HLS which deviate from those of the National Health Survey are provided below.

Sample selection

The HLS sample consists of adult respondents to the National Health Survey 2017-18 who:

• Agreed to be contacted for a follow up survey
• Provided a name and phone number, and
• Did not answer the NHS 2017-18 as a proxy.
  
  

Method and collection period

The HLS was conducted by Computer Assisted Telephone Interview (CATI). The HLS was enumerated from January 2018 to August 2018.

When considering survey results with data from another source, care must be taken to ensure that any differences between the collection periods take into consideration the possible effect of those differences on the data, for example, seasonal differences and effects of holidays. This data may have been collected over a different financial year to the original NHS 2017-18 interview, and income details reported for the HLS 2018 reflect the original information provided by the respondents.

Proxy interviews (where another person provides responses on behalf of the selected person) were not permitted in the HLS 2018.

Respondents were asked all questions in the HLQ no matter what their answers were to previous questions. Responses for each question were required to be able to move forward in the survey. A non-response option (e.g. ‘Don’t know’) was not available. If unsure respondents were encouraged to pick the response that they first thought of, or that would describe them best out of the options available.