|•||assessing a person's ability to recognize whether a photograph is of someone previously seen or someone new,|
|•||measuring the skill of a medical diagnostician in distinguishing X-rays displaying tumors from those showing healthy tissue,|
|•||finding the intensity of a sound that can be heard 80% of the time, and|
|•||determining whether a person can identify which of several words has been presented on a screen, and whether identification is still possible if the person reports that a word has not appeared at all.|
In each of these situations, the person whose performance we are studying encounters stimuli of different types and must assign distinct responses to them. There is a correspondence1 between the stimuli and the responses so that each response belongs with one of the stimulus classes. The viewer of photographs, for example, is presented with some photos of Old,2 previously seen faces, as well as some that are New, and must respond “old” to the Old faces and “new” to the New. Accurate performance consists of using the corresponding responses as defined by the experimenter.
A correspondence experiment is one in which each possible stimulus is assigned a correct response from a finite set. In complete correspondence experiments, which include all the designs in chapters 1,2,4,6,7,9,10, and 11, this partition is rigidly set by the experimenter. In incomplete corre-____________________