01593nas a2200145   4500008004100000020001400041245007300055210006900128300001200197490000700209520110600216100001501322700001201337856009801349       2010                        eng d  a0033-312300aOnline calibration via variable length computerized adaptive testing0 aOnline calibration via variable length computerized adaptive tes  a140-1570 v753 aItem calibration is an essential issue in modern item response theory based psychological or educational testing. Due to the popularity of computerized adaptive testing, methods to efficiently calibrate new items have become more important than that in the time when paper and pencil test administration is the norm. There are many calibration processes being proposed and discussed from both theoretical and practical perspectives. Among them, the online calibration may be one of the most cost effective processes. In this paper, under a variable length computerized adaptive testing scenario, we integrate the methods of adaptive design, sequential estimation, and measurement error models to solve online item calibration problems. The proposed sequential estimate of item parameters is shown to be strongly consistent and asymptotically normally distributed with a prechosen accuracy. Numerical results show that the proposed method is very promising in terms of both estimation accuracy and efficiency. The results of using calibrated items to estimate the latent trait levels are also reported.1 aChang, Y I1 aLu, H Y  uhttp://www.iacat.org/content/online-calibration-variable-length-computerized-adaptive-testing