Another Perspective on Vocabulary Richness

This article examines the usefulness of vocabulary richness for authorship attribution and tests the assumption that appropriate measures of vocabulary richness can capture an author’s distinctive style or identity. After briefly discussing perceived and actual vocabulary richness, I show that doubling and combining texts affects some measures in computationally predictable but conceptually surprising ways. I discuss some theoretical and empirical problems with some measures and develop simple methods to test how well vocabulary richness distinguishes texts by different authors. These methods show that vocabulary richness is ineffective for large groups of texts because of the extreme variability within and among them. I conclude that vocabulary richness is of marginal value in stylistic and authorship studies because the basic assumption that it constitutes a wordprint for authors is false.