Results are presented of an investigation made to (1) provide a description of the testing models that are currently being used in selected individualized instructional programs, (2) compare three programs along the component parts of the testing model, namely, selection of a program of study, criterion-referenced testing on the unit objectives, assignment of instructional modes, and final year-end assessment, and (3) briefly outline several promising lines of research in connection with the testing methods and decision procedures for individualized instructional programs. The three programs selected for study were: Individually Prescribed Instruction, Program for Learning in Accordance with Needs, and Mastery Learning. An introduction, which includes a brief history, the content areas covered, and an indication of the extent of implementation, is provided for each instructional model. In addition, a description of each instructional paradigm and details on the testing model are provided. An attempt is made to pinpoint the decision points in each model, spelling out the consequences of the various possible actions in relation to each of the "possible true states of nature." A lengthy list of references is included. (DB)