'Total Net Household Income' as Demographic Standard Variables for Social Surveys.

In academically driven social surveys, income is an indicator of the socio-economic status. It is used as an explanatory variable in mobility studies and as a social-demographic background item in inequality research. In most cases, information about the income brackets in which the net household income is located is usually enough for a comparative analysis of social structure because the respondent's socio-economic position is determined by his access to the monetary resources of the household in which he lives. Frequently, different questions are formulated for the various sub-populations information is requested about different income resources. For example, the households of self-employed persons are surveyed using an adapted version of the income question. The reduction of the rate of non-response to the sensitive, open-ended income question often succeeds by presenting the respondent with a list of income categories in which each category has a randomly generated code letter. The fact that the code letters are not in any order gives both sides ? the respondents and the interviewers ? the impression that the interviewer cannot deduce the level of income from the response. In the following sections, we shall compare and contrast two instruments for the measurement of income: the first was used in Round 1 of the European Social Survey (ESS) to measure net household income; the second was used in Round 4 of the ESS.