Discrimination in test characteristics refers to what?

Discrimination in test characteristics refers to what?

• A. The test's ability to differentiate between high- and low-ability examinees
• B. The test's readability
• C. The test's administration time
• D. The test's cost

Answer: (A)

Discrimination describes an item's ability to separate higher-ability test takers from lower-ability ones. A well-discriminating item tends to be answered correctly by those with higher overall ability and less so by those with lower ability, producing a noticeable difference in performance between the groups. In practice this is shown by correlations between an item's score and the total test score (item-total or point-biserial correlation) or by comparing how well top versus bottom groups do on the item. If high-ability examinees outperform low-ability examinees, the item has positive discrimination and contributes meaningfully to measuring ability. If performance is about the same across ability levels, discrimination is low; if the lower-ability group does better, discrimination is negative. This concept is distinct from readability (how easy the text is to read), administration time (how long the test takes to give), or cost (expense of administering the test).

Discrimination describes an item's ability to separate higher-ability test takers from lower-ability ones. A well-discriminating item tends to be answered correctly by those with higher overall ability and less so by those with lower ability, producing a noticeable difference in performance between the groups. In practice this is shown by correlations between an item's score and the total test score (item-total or point-biserial correlation) or by comparing how well top versus bottom groups do on the item. If high-ability examinees outperform low-ability examinees, the item has positive discrimination and contributes meaningfully to measuring ability. If performance is about the same across ability levels, discrimination is low; if the lower-ability group does better, discrimination is negative. This concept is distinct from readability (how easy the text is to read), administration time (how long the test takes to give), or cost (expense of administering the test).