Scale format effects on response option interpretation and use

When designing questionnaires, researchers often use different scale formats, which vary on the dimensions polarity (unipolar versus bipolar endpoint labels) and the numbering of the response options (e.g., only positive numbers versus positive and negative numbers). This study uses survey experiments and cognitive interviews, to test specific hypotheses regarding how scale formats' polarity and their numbering might affect (1) observed response distributions and (2) the meaning of response options. In line with our theoretical predictions, the results unveil consistent differences in the interpretation and use of the scale formats as a function of their polarity and numbering. Therefore, alternative formats cannot be used interchangeably as the scale formats are differently interpreted and used. In addition, researchers need to choose scale formats and interpret scale responses in accordance with respondents' interpretations.