The goal of the current study was to introduce a new stopping rule for computerized adaptive testing. The predicted standard error reduction stopping rule (PSER) uses the predictive posterior variance to determine the reduction in standard error that would result from the administration of additional items. The performance of the PSER was compared to that of the minimum standard error stopping rule and a modified version of the minimum information stopping rule in a series of simulated adaptive tests, drawn from a number of item pools. Results indicate that the PSER makes efficient use of CAT item pools, administering fewer items when predictive gains in information are small and increasing measurement precision when information is abundant.
KeywordsComputerized Adaptive Testing (CAT); Stopping Rule; Testing Burden According to Wainer (2000) an adaptive test can be considered complete after a predetermined number of items have been administered, when a predetermined level of measurement precision has been reached, or when a predetermined length of time has elapsed. The two most commonly used methods for determining when a computerized adaptive test is complete are the fixed length and variable length stopping rules.Under a fixed length stopping rule, an adaptive test is terminated when a predetermined number of items have been administered. Accordingly, all examinees are administered the same number of items, regardless of the degree of measurement precision achieved upon termination of the test. The primary advantage of the fixed length stopping rule is its simplicity. However, one consequence of the implementation of the fixed length stopping rule is that examinees will be measured with different degrees of precision, with larger measurement error typically occurring at extreme trait levels. Additionally, a fixed length stopping rule may limit the efficiency of an adaptive test through the unnecessary administration of items that contribute little information about examinee trait level.In contrast, variable length stopping rules typically seek to achieve a certain degree of measurement precision for all examinees, even when doing so means that some examinees are given more items than others. Two types of variable length stopping rules have been Send correspondence to: Seung W. Choi, s-choi@northwestern.edu, Northwestern University Feinberg School of Medicine, Department of Medical Social Sciences, 710 N. Lake Shore Dr., Chicago, IL 60611, USA, Phone: (312) Fax: (312) 503-9800.
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Author ManuscriptEduc Psychol Meas. Author manuscript; available in PMC 2011 January 27.
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript used (Dodd, Koch, & De Ayala, 1993). These are the standard error (SE) stopping rule and the minimum information stopping rule. Of these, the most commonly used has been the SE stopping rule, which terminates an adaptive test when a predetermined standard error has been reached for the most recent examinee trait estimate (Boyd, Dodd, & Choi, 2010)....