Using Only Numeric Labels Instead of Verbal Labels: Stripping Rating Scales to Their Bare Minimum in Web Surveys

Abstract

With the increasing use of smartphones in web surveys, considerable efforts have been devoted to reduce the amount of screen space taken up by questions. An emerging stream of research in this area is aimed at optimizing the design elements of rating scales. One suggestion that has been made is to completely abandon verbal labels and use only numeric labels instead. This approach deliberately shifts the task of scale interpretation to the respondents and reduces the information given to them with an intention to reduce their response burden while still preserving the scale meaning. Following prior research, and by drawing on the established model of the cognitive response process, we critically tested these assumptions. Based on a web survey experiment, we found that omitting verbal labels and using only numeric labels instead pushed respondents to focus their responses on the endpoints of a rating scale. Moreover, drawing on response time paradata, we showed that their response burden was not reduced when presented with only numeric labels; quite the opposite was the case, especially when respondents answered the scale with only numeric labels for the first time, which seemed to entail additional cognitive effort. Based on our findings, we advise against using only numeric labels for rating scales in web surveys.