Assessing data from summary questions about earnings and income

In short surveys, or in surveys that prioritise other content domains, earnings and income are often elicited using small sets of summary questions. This contrasts with the detailed questions recommended for surveys that focus on earnings and income, that ask source by source. We evaluate earnings and income data collected with summary questions in a series of recent web-surveys: the Understanding Society COVID-19 Study. The fact that many COVID-19 Study respondents also contemporaneously answered the main annual Understanding Society survey provides individual- and household-level validation data. We find that measures of household earnings and income in the COVID-19 Study are noisier than those from the main annual Understanding Society survey, and that there is evidence of systematic under-reporting for household totals. However, for most measures and samples, we find that measurement errors in the COVID-19 Study are substantively uncorrelated with true values. We conclude that the COVID-19 Study collected valuable data on earnings and income, and more broadly, that summary questions on earnings or income can be a useful data collection tool.