00562nas a2200121   4500008004100000245011200041210006900153260004500222100001800267700001500285700001700300856012300317       2006                        eng d00aKernel-smoothed DIF detection procedure for computerized adaptive tests (Computerized testing report 00-08)0 aKernelsmoothed DIF detection procedure for computerized adaptive  aNewton, PAbLaw School Admission Council1 aNandakumar, R1 aBanks, J C1 aRoussos, L A  uhttp://mail.iacat.org/content/kernel-smoothed-dif-detection-procedure-computerized-adaptive-tests-computerized-testing02037nas 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-setting00555nas a2200109   4500008004100000245013000041210006900171260004500240100001800285700001500303856012700318       2001                        eng d00aCATSIB: A modified SIBTEST procedure to detect differential item functioning in computerized adaptive tests (Research report)0 aCATSIB A modified SIBTEST procedure to detect differential item   aNewton, PAbLaw School Admission Council1 aNandakumar, R1 aRoussos, L  uhttp://mail.iacat.org/content/catsib-modified-sibtest-procedure-detect-differential-item-functioning-computerized-adapti-000556nas a2200109   4500008004100000245013000041210006900171260004600240100001800286700001500304856012700319       1997                        eng d00aCATSIB: A modified SIBTEST procedure to detect differential item functioning in computerized adaptive tests (Research report)0 aCATSIB A modified SIBTEST procedure to detect differential item   aNewtown, PA: Law School Admission Council1 aNandakumar, R1 aRoussos, L  uhttp://mail.iacat.org/content/catsib-modified-sibtest-procedure-detect-differential-item-functioning-computerized-adaptive01951nas a2200133   4500008004100000245005600041210005600097260002100153520149700174653003401671100001801705700001701723856007701740       1997                        eng d00aValidation of CATSIB To investigate DIF of CAT data0 aValidation of CATSIB To investigate DIF of CAT data  aChicago, IL. USA3 aThis paper investigates the performance of CATSIB (a modified version of the SIBTEST computer program) to assess differential item functioning (DIF) in the context of computerized adaptive testing (CAT). One of the distinguishing features of CATSIB is its theoretically built-in regression correction to control for the Type I error rates when the distributions of the reference and focal groups differ on the intended ability. This phenomenon is also called impact. The Type I error rate of CATSIB with the regression correction (WRC) was compared with that of CATSIB without the regression correction (WORC) to see if the regression correction was indeed effective. Also of interest was the power level of CATSIB after the regression correction. The subtest size was set at 25 items, and sample size, the impact level, and the amount of DIF were varied. Results show that the regression correction was very useful in controlling for the Type I error, CATSIB WORC had inflated observed Type I errors, especially when impact levels were high. The CATSIB WRC had observed Type I error rates very close to the nominal level of 0.05. The power rates of CATSIB WRC were impressive. As expected, the power increased as the sample size increased and as the amount of DIF increased. Even for small samples with high impact rates, power rates were 64% or higher for high DIF levels. For large samples, power rates were over 90% for high DIF levels. (Contains 12 tables and 7 references.) (Author/SLD)10acomputerized adaptive testing1 aNandakumar, R1 aRoussos, L A  uhttp://mail.iacat.org/content/validation-catsib-investigate-dif-cat-data