Multiple-choice versus short-response items: Differences in omit behaviour

The overall rate of omission of items for 28331 17-year-old Australian students on a high-stakes test of achievement in the common elements or cognitive skills of the senior school curriculum is reported for a subtest in multiple-choice format and a subtest in short-response format. For the former, the omit rates were minuscule and there was no significant difference by gender or by type of school attended. For the latter, where an item can be ʹworthʹ up to five times that of a single multiple-choice item, the omit rates were between 10 and 20 times that for multiple-choice and the difference between male and female omit rate was significant as was the difference between students from government and nongovernment schools. For both formats, females from single-sex schools omitted significantly fewer items than did females from coeducational schools. Some possible explanations of omit behaviour are alluded to.