86; CI 0.84–0.88), pathophysiology (0.83; CI 0.78–0.87) and dosing (0.82; CI 0.79–0.85). Dosing items were statistically more difficult than therapeutics (P = 0.013), but not pathophysiology items (P = 0.71). The overall discrimination index was 0.24 (CI 0.23–0.25). The rank order of increasing discrimination by content was therapeutics (0.23; CI 0.22–0.24), pathophysiology (0.23; CI 0.20–0.25) and dosing (0.25;

CI 0.24–0.27). Dosing items were also statistically more discriminatory than therapeutics Selumetinib molecular weight (P = 0.02) but not pathophysiology items (P = 0.11). Using a two-way ANOVA the difficulty of items by format and content was simultaneously examined (Table 5). Overall, the ANOVA P values were 0.09 for format, 0.36 for content and 0.47 for the interaction term format*content. Using a separate two-way ANOVA for discrimination, format and content were equally but not significantly influential (P = 0.6), and the interaction term had no effect (P = 0.99). Overall, the results demonstrate that Case-based formatted items are of greater difficulty compared to Standard or Statement item formats and that they provided greater discrimination than Standard items. The two-way

ANOVA (format*content) Metabolism inhibitor indicates that item format is more important than content matter in determining the difficulty of items, but content and format are equally important in determining item discrimination. The authors also realized difficulty and discrimination are approximately 60% correlated; however, it is possible to have a difficult item that is not discriminating, because the difficulty is beyond the comprehension of the class. These results differ from those reported at another college of pharmacy which found that case-based items had lower discrimination scores but no differences in difficulty compared to non-case-based items.[2] However, that study did not specify whether they used parametric ID-8 or non-parametric statistical tests. Given that

means were reported, it can be assumed data were analysed with parametric tests. For that reason, difficulty measurements may not have been appropriately assessed and may have been the victim of type II error. Another reason that may account for differences could have been that non-Case-based items in this current study were separated into other categories (e.g. specific content). A post hoc analysis of these data showed that Case-based items had a higher difficulty level than non-Case-based items (0.81 versus 0.87; P < 0.001). Additionally, the authors of this study conducted a post hoc analysis which also found that Case-based items had greater discrimination than non-Case-based items (0.25 versus 0.23; P = 0.041). Interestingly, this is contradictory to Phipps and Brackbill, who showed that Case-based items were less discriminatory than non-Case-based items.