The Effects of Vignette Scoring on Reliability and Validity of Self-Reports.

Abstract

The research presented in this article combines mathematical derivations and empirical results to investigate effects of the nonparametric anchoring vignette approach proposed by King, Murray, Salomon, and Tandon on the reliability and validity of rating data. The anchoring vignette approach aims to correct rating data for response styles to improve comparability across individuals and groups. Vignettes are used to adjust self-assessment responses on the respondent level but entail significant assumptions: They are supposed to be invariant across respondents, and the responses to vignette prompts are supposed to be without error and strictly ordered. This article shows that these assumptions are not always met and that the anchoring vignette approach leads to higher Cronbach's alpha values and increased correlations among adjusted variables regardless of whether the assumptions of the approach are met or violated. Results suggest that the underlying assumptions and effects of the anchoring vignette approach should be carefully examined as the increased correlations and reliability estimates can be observed even for response variables that are independent random draws and uncorrelated with any other variable.