title: A Confirmatory Analysis of Item Reliability Trends (CAIRT): Differentiating True Score and Error Variance in the Analysis of Item Context Effects.
abstract: Numerous studies have shown increasing item reliabilities as an effect of the item position in personality scales. Traditionally, these context effects are analyzed based on item-total correlations. This approach neglects that trends in item reliabilities can be caused either by an increase in true score variance or by a decrease in error variance. This article presents the Confirmatory Analysis of Item Reliability Trends (CAIRT) that allows estimating both trends separately within a structural equation modeling framework. Results of a simulation study prove the CAIRT method to provide reliable and independent parameter estimates; the power exceeds the analysis of item-total correlations. We present an empirical application to self- and peer ratings collected in an Internet-based experiment. Results show that reliability trends are caused by increasing true score variance in self-ratings and by decreasing error variance in peer ratings.
authors.affiliation: a German Institute for International Educational Research , Frankfurt am Main , Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hartig
authors.affiliation: b Justus-Liebig-Universität , Gie𝒷en , Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Hölzel
authors.affiliation: c Johann Wolfgang Goethe-Universität , Frankfurt am Main , Germany.
authors.forename: Helfried
authors.initials: H
authors.lastname: Moosbrugger