The effect of familiarity with the response category labels on item response to Likert scales

Surveys in the social sciences often employ rating scales anchored by response category labels such as "strongly (dis)agree" or "completely (dis)agree." Although these labels may exert a systematic influence on responses since they are common to all items, academic research on the effect of different labels is surprisingly scarce. In order to help researchers choose appropriate category labels, we contrast the intensity hypothesis (which posits that response categories are endorsed less frequently if the labels are more extreme) with the familiarity hypothesis (which states that response categories are endorsed more frequently if the labels are more common in day-to-day language). In a series of studies we find consistent support for the familiarity hypothesis. Our results have important implications for the appropriate use of category labels in multilingual surveys, and we propose a procedure based on Internet search engine hits to equate labels in different languages in terms of familiarity.