01614nas a2200145   4500008003900000245009500039210006900134300001200203490000700215520113800222100001801360700001801378700001901396856005301415       2008                          d00aA Strategy for Controlling Item Exposure in Multidimensional Computerized Adaptive Testing0 aStrategy for Controlling Item Exposure in Multidimensional Compu  a215-2320 v683 a<p>Although computerized adaptive tests have enjoyed tremendous growth, solutions for important problems remain unavailable. One problem is the control of item exposure rate. Because adaptive algorithms are designed to select optimal items, they choose items with high discriminating power. Thus, these items are selected more often than others, leading to both overexposure and underutilization of some parts of the item pool. Overused items are often compromised, creating a security problem that could threaten the validity of a test. Building on a previously proposed stratification scheme to control the exposure rate for one-dimensional tests, the authors extend their method to multidimensional tests. A strategy is proposed based on stratification in accordance with a functional of the vector of the discrimination parameter, which can be implemented with minimal computational overhead. Both theoretical and empirical validation studies are provided. Empirical results indicate significant improvement over the commonly used method of controlling exposure rate that requires only a reasonable sacrifice in efficiency.</p>
1 aLee, Yi-Hsuan1 aIp, Edward, H1 aFuh, Cheng-Der  uhttp://epm.sagepub.com/content/68/2/215.abstract