During 45 cognitive interviews conducted in the laboratory over the telephone, income and other household and demographic data were obtained from respondents. We found respondents used heuristics that make the task easier for themselves.
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.