%0 Journal Article %J Applied Psychological Measurement %D 2001 %T a-Stratified multistage computerized adaptive testing with b blocking %A Chang, Hua-Hua %A Qian, J. %A Ying, Z. %X Chang & Ying’s (1999) computerized adaptive testing item-selection procedure stratifies the item bank according to a parameter values and requires b parameter values to be evenly distributed across all strata. Thus, a and b parameter values must be incorporated into how strata are formed. A refinement is proposed, based on Weiss’ (1973) stratification of items according to b values. Simulation studies using a retired item bank of a Graduate Record Examination test indicate that the new approach improved control of item exposure rates and reduced mean squared errors. %B Applied Psychological Measurement %V 25 %P 333-341 %@ 0146-6216 %G eng