ITEMS AND PERSONS: FORMAL DUALS AND PSYCHOLOGICAL DIFFERENCES.

A matrix of the responses of persons (rows) to items (columns) can be analyzed for persons as the dual of the usual analyses for items. In personality tests, the stability of items varies with mean distance between the item and the points for persons, and the dual holds for persons. For items, the item- test correlation varies somewhat with stability and with the frequency of appropriate response processes (i.e., Ss answering the item as E intended them to), but stability and appropriateness are not correlated. For persons, the per- son-group correlation is independent of stability and appropriateness, these latter variables being correlated. Thus the pattern of relationships among item indices is different from that for the dual indices for people. Persons being complex, they approach personality test items in diverse ways about which little is known today.