People do not always answer questions regarding their household's income the way the question designer expected them to. During 45 cognitive interviews conducted in the laboratory over the telephone, income and other household and demographic data were obtained from respondents. From observation of both verbal and non-verbal behaviors during interviews and from debriefings of respondents immediately post-interview, we have collected a body of information on how people interpret and answer questions on many income sources. We found respondents used heuristics that make the task easier for themselves. Respondents can be inconsistent in the interpretation of "in the past 12 months." Respondents answer with more assurance for some people in the household than for others. They are more confident of their answers for certain types of income than for others. Asking income on the telephone can pose problems if accurate amounts are the goal. These and other findings are discussed.
