There is currently limited empirical evidence available to allow a proper comparison of the relative merits of whole-script marking and item-level marking.
However, the limited research carried out to date suggests that item-level marking seems to be at least as reliable as whole-script marking, and under some conditions is likely to be more reliable than whole-script marking.
Specifically, item-level marking may:
- remove the ‘halo effect’ that means examiners carry forward preconceived ideas about the level of a student’s understanding based on his or her answers to previous unrelated items
- eliminate the most extreme cases of poor marking reliability, which impact significantly upon public confidence, although it is unlikely to make it more likely that a student will receive the correct grade
- improve the reliability of marking, particularly for the highest performing students
It is suggested that further research in this area is needed.