Table 4 The statistical analysis is shown based on the question type of the variables of corrected difficulty by chance (IDiffCor), question discrimination according to the biserial correlation coefficient (rpbis), item response theory, and finally the number of characters in the statement, responses, and overall question characters. It can be observed that clinical cases associated with images and negative questions exhibit high difficulty and poorer discrimination compared to other questions. Regarding characters, questions with longer statements and shorter answers demonstrate better discrimination. Typical clinical cases and questions that exhibit better discrimination fulfill these criteria for character distribution
Corrected difficulty index: Kruskal-Wallis Test H = 22.69 DF = 3 P < 0.001. | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 0.6377 | 1523.8 | 4.65 |
CC with Image | 393 | 0.5754 | 1392.3 | -1.36 |
Negative | 445 | 0.5465 | 1343.9 | -2.79 |
Test | 726 | 0.5800 | 1393.5 | -1.94 |
Overall | 2890 | 1445.5 | ||
The point biserial correlation coefficient: Kruskal-Wallis Test on rpbis H = 52.22 DF = 3 P < 0.001. | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 0.3225 | 1529.9 | 5.01 |
CC with Image | 393 | 0.2689 | 1188.3 | -6.57 |
Negative | 445 | 0.2951 | 1402.8 | -1.17 |
Test | 726 | 0.3127 | 1456.7 | 0.42 |
Overall | 2890 | 1445.5 | ||
Discrimination measured by the two-parameter item response theory model: H = 44.13 DF = 3 P < 0.001 | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 0.7520 | 1517.1 | 4.25 |
CC with Image | 393 | 0.6033 | 1210.5 | -6.01 |
Negative | 445 | 0.6712 | 1387.9 | -1.58 |
Test | 726 | 0.7422 | 1477.2 | 1.18 |
Overall | 2890 | 1445.5 | ||
Variable characters stem: Kruskal-Wallis Test H = 1634.79 DF = 3 P < 0.001 | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 390.0 | 2044.2 | 35.52 |
CC with Image | 393 | 309.0 | 1641.4 | 5.01 |
Negative | 445 | 104.0 | 715.2 | -20.07 |
Test | 726 | 106.0 | 693.6 | −28.06 |
Overall | 2890 | 1445.5 | ||
Variable characters answers: H = 20.24 DF = 3 P < 0.001. | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 171.0 | 1419.1 | -1.57 |
CC with Image | 393 | 156.0 | 1315.0 | -3.34 |
Negative | 445 | 216.0 | 1531.9 | 2.37 |
Test | 726 | 208.0 | 1511.4 | 2.46 |
Overall | 2890 | 1445.5 | ||
Variable total characters: H = 742.74 DF = 3 P < 0.001 | ||||
Question Type | N | Median | Ave Rank | Z |
Clinical Case | 1326 | 613.5 | 1858.4 | 24.49 |
CC with Image | 393 | 510.0 | 1529.4 | 2.15 |
Negative | 445 | 347.0 | 979.6 | -12.81 |
Test | 726 | 341.0 | 931.6 | -19.18 |
Overall | 2890 | 1445.5 | ||