Differences in answers in Internet and traditional surveys can be due to selection, mode, or context effects. The authors exploit unique experimental data to analyze mode and context effects controlling for arbitrary selection. The Health and Retirement Study (HRS) surveys a random sample of the US 50+ population, with CAPI or CATI core interviews once every two years. In 2003 and 2005, random samples were drawn from HRS respondents in 2002 and 2004 willing and able to participate in an Internet interview. Comparing core and Internet survey answers of the same people, the authors analyze mode and context effects, controlling for selection. They focus on household assets, for which mode effects in Internet surveys have rarely been studied. They find some large differences between the first Internet survey and the other three surveys which they interpret as a context and question wording effect rather than a pure mode effect.
Van Soest, Arthur and Arie Kapteyn, Mode and Context Effects in Measuring Household Assets. Santa Monica, CA: RAND Corporation, 2009. https://www.rand.org/pubs/working_papers/WR668.html.
Van Soest, Arthur and Arie Kapteyn, Mode and Context Effects in Measuring Household Assets, RAND Corporation, WR-668, 2009. As of February 15, 2024: https://www.rand.org/pubs/working_papers/WR668.html