Patricia Martinkova is a Fulbright-Masaryk fellow with the Center for Statistics in the Social Sciences at University of Washington.
Many Czech colleges and universities run their own admission tests. Several years ago, there was a suggestion to require reporting of Cronbach’s alpha, a measure of reliability, for all higher education admissions tests. This study first aimed to explain the statistical groundings for Cronbach’s alpha, to stress its assumptions and to research alternative reliability estimates in more complicated designs. As a secondary outcome, a new estimate of reliability, logistic alpha, was proposed for binary items.
The talk will present the work on the development of the new reliability estimate and the simulation study that compares the logistic alpha with existing estimators of reliability in IRT models. Findings will be discussed in the context of actual admission data.