TY - JOUR T1 - Methods for restricting maximum exposure rate in computerized adaptative testing JF - Methodology: European Journal of Research Methods for the Behavioral and Social Sciences Y1 - 2007 A1 - Barrada, J A1 - Olea, J. A1 - Ponsoda, V. KW - computerized adaptive testing KW - item bank security KW - item exposure control KW - overlap rate KW - Sympson-Hetter method AB - The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method (Revuelta & Ponsoda, 1998), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy. (PsycINFO Database Record (c) 2007 APA, all rights reserved) PB - Hogrefe & Huber Publishers GmbH: Germany VL - 3 SN - 1614-1881 (Print); 1614-2241 (Electronic) ER - TY - JOUR T1 - Constraining item exposure in computerized adaptive testing with shadow tests JF - Journal of Educational and Behavioral Statistics Y1 - 2004 A1 - van der Linden, W. J. A1 - Veldkamp, B. P. KW - computerized adaptive testing KW - item exposure control KW - item ineligibility constraints KW - Probability KW - shadow tests AB - Item-exposure control in computerized adaptive testing is implemented by imposing item-ineligibility constraints on the assembly process of the shadow tests. The method resembles Sympson and Hetter’s (1985) method of item-exposure control in that the decisions to impose the constraints are probabilistic. The method does not, however, require time-consuming simulation studies to set values for control parameters before the operational use of the test. Instead, it can set the probabilities of item ineligibility adaptively during the test using the actual item-exposure rates. An empirical study using an item pool from the Law School Admission Test showed that application of the method yielded perfect control of the item-exposure rates and had negligible impact on the bias and mean-squared error functions of the ability estimator. PB - American Educational Research Assn: US VL - 29 SN - 1076-9986 (Print) ER -