This nationally representative survey, conducted by the ESRI on behalf of the Health Research Board (HRB), was designed to measure the extent of psychological distress and self-reported mental health problems in the Irish population, and to determine the socio-demographic characteristics of the Irish adult population who were experiencing symptoms of psychological distress or who had reported mental health problems in the previous year. The survey used a telephone survey methodology of the general population in the Republic of Ireland, in 2005-2006. Telephone numbers were drawn on a random probability basis and quotas were set for age, gender and social class.

Probability: Simple random. Telephone numbers were drawn on a random, probability basis. In order to ensure geographic coverage, an initial set of random clusters (or sampling areas) was selected from the GeoDirectory. This is a comprehensive list of private households in the Republic of Ireland; it is compiled jointly by the Ordnance Survey and An Post. The initial sample of areas was then employed to generate a random telephone sample using random digit dialling (RDD). Using this system, different phone numbers for each month are selected. The matching stem of each phone number is marked up on a file, thus ensuring that phone numbers can not be used again for at least another two years. As a result, there are no duplicates in the HRB dataset for this survey.

Telephone interview