A COMPARISON OF PROCEDURES TO DETECT ITEM PARAMETER DRIFT

Monte carlo methods were used to compare several measures of item para meter drift. Number of examinees, number of items, and number of drift items in the test were manipulated. Overall, Lord's chi(2) measure wa s the most effective in identifying items that exhibited drift. Howeve r, the measure was accurate only when the studied item's c parameter w as constrained to be equal across the two assessment years. Of the rem aining measures, the best methods (a z test based on Raju's exact unsi gned integral, the NAEP BILOG/PARSCALE computer program's chi(2) by su bgroup, and Kim and Cohen's closed-interval signed-area measure) requi red empirical estimates of critical values for the test statistics in order to function well. This requirement detracts from their usefulnes s.