Many scales contain both positively and negatively worded items. Reverse recoding of negatively worded items might not be enough for them to function as positively worded items do. In this study, we commented on the drawbacks of existing approaches to wording effect in mixed-format scales and used bi-factor item response theory (IRT) models to…

Two alternatives to traditional item analysis and reliability estimation procedures are considered for determining the difficulty, discrimination, and reliability of optional items on essay and other tests. A computer program to compute these measures is described, and illustrations are given. (SLD)