“…They can be assessed in terms of their power to discriminate good from poor candidates (as measured by the QEX) or by their level of difficulty (as measured by the mean mark). Assessment on the basis of the level of difficulty alone (Harris and Buckley‐Sharp, 1968) would regard question 99 (Table 2) as a poor question since it has a mean mark of 0.78, suggesting that the question is too easy. On the other hand, a relatively high QEX (0.45) indicates that those who answered it correctly were the more able students.…”