The Labeling of Anchor Points and the Occurrence of Zero-Width Intervals

Abstract

The labeling of the anchor points of a response scale may tempt the judges participating in scale intervals studies to assign zero-width intervals to these points by choosing the upper and lower bound equal to an extreme of the continuum. The phenomenon of assigning zero-width intervals occurs more frequently when extreme wording is used for an anchor point label and when the response scale consists of more than five response options. Although all-inclusive response scales would encompass the full spectrum of possible experiences, there uses is likely to make anchor points redundant for part of the respondents using such a response scale.