An experiment testing six formats of 101-point rating scales

• Compared six types of 101-point feeling thermometer questions.
• Visual analog scales elicit fewer rounded answers than open-ended questions.
• Completion time is faster for visual analog scales and open-ended questions.
• Item nonresponse rates are similar across question types.

Although 101-point feeling thermometer questions are frequently used in population surveys and political polls, the measurement error associated with this question type has raised some concerns. One challenge of using this type of question arises from the tendency for respondents to round their answers. That is, rather than providing a precise answer, respondents provide an answer that is divisible by 5 which on at least some occasions is rounded up or down from a more precise (unrounded) value. Several national surveys currently use an open-ended numeric text input format for the feeling thermometer questions, which may exacerbate the response rounding. This study presents findings from two Web survey experiments that examine six formats of 101-point rating scales. The findings show that visual analog scales (VAS) result in fewer rounded answers than open-ended numeric text input, while item nonresponse rates are similar across these questions types. Also, responding to VAS tends to be easier than open-ended format. This study concludes by discussing the application of VAS for feeling thermometer questions and future research directions.