Choosing the Number of Categories in Agree–Disagree Scales

Abstract

Although agree–disagree (AD) rating scales suffer from acquiescence response bias, entail enhanced cognitive burden, and yield data of lower quality, these scales remain popular with researchers due to practical considerations (e.g., ease of item preparation, speed of administration, and reduced administration costs). This article shows that if researchers want to use AD scales, they should offer 5 answer categories rather than 7 or 11, because the latter yield data of lower quality. This is shown using data from four multitrait-multimethod experiments implemented in the third round of the European Social Survey. The quality of items with different rating scale lengths were computed and compared.