ABSTRACT
Researchers who build norm-referenced tests approach the task differently from those who build criterion-referenced tests. NRTs are intentionally built to be of medium difficulty. Specifically, items that are answered correctly by about 50% of the examinees in tryouts during test development are favored in the selection of items for the final versions of the tests. It is essential that an NRT be of medium difficulty because this level of difficulty facilitates the comparison of an individual with a group. This can be seen most easily at the extremes. For instance, if a researcher foolishly built an NRT that was so easy that all participants in the norm group got every item right, the researcher could not interpret scores in terms of who has a higher or lower score than other examinees because everyone would have the same score. The same problem would occur if a researcher built an NRT that was so difficult that all the examinees got all the items wrong.
