Straightlining: Overview of Measurement, Comparison of Indicators, and Effects in Mail-Web Mixed-Mode Surveys

Straightlining occurs when survey respondents give identical (or nearly identical) answers to items in a battery of questions using the same response scale, which may reduce data quality. Despite its potential importance, research examining straightlining does not use a standard measurement technique. Further, while mixed-mode studies are increasing in prevalence, few studies compare straightlining behavior in mail versus web surveys. Our article has the following goals: (1) describe and evaluate methods for detecting straightlining and (2) examine effects of education and mode of administration on straightlining in two mail/web mixed-mode surveys. Data for Study 1 are from a 2010 survey of alcohol beliefs and consumption in which 7,200 young adults were sampled from driver's license records in Wisconsin and randomly assigned to mail-web (mail followed by web) or web-mail (web followed by mail) treatments. Data for Study 2 are from a 2013 survey about a public university and its affiliated health organizations that used an address-based sample and randomly assigned households to one of the three experimental groups: mail-only, web-only, and web-mail. We identify and examine five methods for measuring straightlining: simple nondifferentiation, mean root of pairs, maximum identical rating, standard deviation of battery, and scale point variation. The overall results replicate previously reported findings of a negative association between education and straightlining behaviors except for the standard deviation of battery measure in Study 1. Controlling for gender, race/ethnicity, and education, mode of administration was not significantly related to straightlining for any of the measures, suggesting straightlining behavior is stable across mail and web forms of self-administration.