Computerized Classification Testing under Practical Constraints with a Polytomous Model

A study was conducted to extend the sequential probability ratio testing (SPRT) procedure with the polytomous model under some practical constraints in computerized classification testing (CCT), such as methods to control item exposure rate, and to study the effects of other variables, including item information algorithms, test difficulties, item pool sizes, and widths of the indifference region in SPRT. SPRT was applied for polytomous items under the generalized partial credit model of E. Muraki (1992). Monte Carlo simulation technique was used. Independent variables manipulated were: (1) item information algorithm; (2) item exposure control methods; (3) location of the theta cut point (test difficulty); (4) item pool size; and (5) width of indifference region in SPRT. Item parameters from the 1996 National Assessment of Educational Progress were used to build the item pool, and item response data were generated for 10,000 simulated examinees. Polytomous items were found to work well with the SPRT procedure in CCT. Considerations in using the procedure are discussed. (Contains 5 tables and 18 references.) (SLD)