How Long Do Respondents Think Online Surveys Should Be? New Evidence from Two Online Panels in Germany

In recent years, the number of surveys, especially online surveys, has increased dramatically. Due to the absence of interviewers in this survey mode (who can motivate the respondents to continue answering), some researchers and practitioners argue that online surveys should not be longer than 20 minutes. However, so far, there has been little research investigating how long respondents think that online surveys should or could be. In this study, we therefore asked respondents of two online panels in Germany (one probability-based panel and one nonprobability panel) about their opinions on the ideal and maximum lengths of surveys. We also investigated whether socio-demographic, personality-related, and survey-related variables were associated with the ideal and maximum lengths reported by respondents. Finally, we compared the stated and observed survey lengths to evaluate the extent to which respondents are able to accurately estimate survey length. Our results suggest that the ideal length of an online survey is between 10 and 15 minutes and the maximum length is between 20 and 28 minutes, depending on the measure of central tendency (mean or median) used and the panel. Moreover, we found significant effects of socio-demographics (gender, age, education, and number of persons in household), of personality traits, and survey-related questions (whether the respondents liked the survey, found it easy, and answered from a PC) on at least one of the dependent variables (ideal or maximum lengths). Finally, we found only small differences (less than two minutes) between stated and observed lengths