Between task complexity and question sensitivity: nonresponse to the income question in the 2008–2018 European Social Survey

Item nonresponse is an under-researched aspect in cross-national surveys. In this study, we explore nonresponse to the question about a household’s total net income in the European Social Survey (2008-2018), which had the highest item nonresponse rate across all survey rounds. We examine income nonresponse mechanisms using a dual framework of task complexity and question sensitivity, recognizing that both respondents and country characteristics affect nonresponse patterns. In doing so, we apply multilevel logistic regressions to model two distinct income nonresponse options: "don’t know" answers and refusals to answer the question. We find that task complexity and question sensitivity operate at the individual and country levels, indicating that item nonresponse is a multi-layered phenomenon in the survey process.