The target population for a survey describes the complete set of units to be studied. A sample survey will generally attempt to achieve a representative sample of the target population. However, the target population may be more detailed than the total population from which the sample is drawn. It may also specify sub-populations that the survey describes. For example, the total population might be all persons aged 15 and over living in private dwellings in a specified area. However, the target population might also specify males and females as sub-populations of interest, requiring the sampling frame to accommodate distinct analysis of these two groups. More generally, sub-groups are often defined by such characteristics as age, gender, ethnicity, employment status or migrant status.
Some surveys with the household as the unit of measure rely on a single respondent (such as the head of household) to provide responses for the household as a whole. This cannot be used for measures of subjective well-being, since the cognitive process of evaluating and responding with respect to one’s own subjective well-being is very different to that of providing an estimate of another householder’s state of mind. Responses to questions on subjective wellbeing are inherently personal, and consequently the unit of measure for subjective well-being must be the individual. This implies that the sampling frame must produce a representative sample of individuals or households as if all individuals are personally interviewed. While this will typically not be an issue for surveys where the individual is the primary unit of analysis, some household surveys may require an additional set of individual weights to derive individual estimates. Surveys where the response is on the basis of “any responsible adult” will in particular be problematic in this regard.
The target age group for measures of subjective well-being will vary with respect to the goals of the research programme. For example, in the context of research on retirement income policies, it may be appropriate to limit the target population to persons aged 65 or older. In general, however, measures of subjective well-being would usually be collected for all the adult population (aged 15 years and older).