02037nas a2200181   4500008004100000020002200041245006400063210006400127260004300191300001200234490000700246520141900253653003201672653003401704100001801738700001701756856008201773       2004                        eng d  a1076-9986 (Print)00aEvaluation of the CATSIB DIF procedure in a pretest setting0 aEvaluation of the CATSIB DIF procedure in a pretest setting  bAmerican Educational Research Assn: US  a177-1990 v293 aA new procedure, CATSIB, for assessing differential item functioning (DIF) on computerized adaptive tests (CATs) is proposed. CATSIB, a modified SIBTEST procedure, matches test takers on estimated ability and controls for impact-induced Type I error inflation by employing a CAT version of the SIBTEST "regression correction." The performance of CATSIB in terms of detection of DIF in pretest items was evaluated in a simulation study. Simulated test takers were adoptively administered 25 operational items from a pool of 1,000 and were linearly administered 16 pretest items that were evaluated for DIF. Sample size varied from 250 to 500 in each group. Simulated impact levels ranged from a 0- to 1-standard-deviation difference in mean ability levels. The results showed that CATSIB with the regression correction displayed good control over Type 1 error, whereas CATSIB without the regression correction displayed impact-induced Type 1 error inflation. With 500 test takers in each group, power rates were exceptionally high (84% to 99%) for values of DIF at the boundary between moderate and large DIF. For smaller samples of 250 test takers in each group, the corresponding power rates ranged from 47% to 95%. In addition, in all cases, CATSIB was very accurate in estimating the true values of DIF, displaying at most only minor estimation bias. (PsycINFO Database Record (c) 2007 APA, all rights reserved)10acomputerized adaptive tests10adifferential item functioning1 aNandakumar, R1 aRoussos, L A  uhttp://mail.iacat.org/content/evaluation-catsib-dif-procedure-pretest-setting