Difference in Generality Between Item Pairs Mediates Effect of Difference in Items’ Lengths on Inter-Item Correlation Size

Abstract

In this study, the author examined potential mediators of the negative relationship between the absolute difference in items’ lengths and their inter-item correlation size. Fifty-two randomly ordered items from five personality scales were administered to 622 university students, and 46 respondents from a survey website rated the items’ readability, clarity, and generality. Based on prior research, the author hypothesized that the difference in mean ratings of item pairs’ generality, but not readability or clarity, would mediate the negative relationship between the difference in the item pairs’ lengths and their inter-item correlation size. In pairs of items, difference in item length was negatively correlated with inter-item correlation size. However, only difference in ratings of generality, not readability or clarity, was associated with correlation size, and as predicted, it mediated the relationship between item length and correlation size. Theoretical and practical implications are discussed.