Specific questions addressed in this study include how time limits affect a test's construct and predictive validities, how time limits affect an examinee's time allocation and test performance, and whether the assumption about how examinees answer items is valid. Interactions involving an examinee's sex and age are studied. Two parallel forms of…

Birnbaum's three-parameter logistic item response model was used to study guessing behavior of low ability examinees on the Graduate Record Examinations (GRE) General Test, Verbal Measure. GRE scoring procedures had recently changed, from a scoring formula which corrected for guessing, to number-right scoring. The three-parameter theory was used…