Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

A new item-fit index is proposed that is both a descriptive measure of deviance of single items and an index for statistical inference. This index is based on assumptions of the dichotomous and polytomous Rasch models for items with ordered categories. A simulation study is described. (SLD)