scholarly journals Constructing Shadow Tests in Variable-Length Adaptive Testing

2018 ◽  
Vol 42 (7) ◽  
pp. 538-552
Author(s):  
Qi Diao ◽  
Hao Ren
Keyword(s):  
Computerized Adaptive Testing ◽  
Educational Measurement ◽  
Adaptive Testing ◽  
Variable Length ◽  
Item Selection ◽  
Original Form ◽  
Content Balancing ◽  
Future Consequences ◽  
Elegant Solution

Imposing content constraints is very important in most operational computerized adaptive testing (CAT) programs in educational measurement. Shadow test approach to CAT (Shadow CAT) offers an elegant solution to imposing statistical and nonstatistical constraints by projecting future consequences of item selection. The original form of Shadow CAT presumes fixed test lengths. The goal of the current study was to extend Shadow CAT to tests under variable-length termination conditions and evaluate its performance relative to other content balancing approaches. The study demonstrated the feasibility of constructing Shadow CAT with variable test lengths and in operational CAT programs. The results indicated the superiority of the approach compared with other content balancing methods.

scholarly journals The Impact of Item Calibration Error on Variable-Length Cognitive Diagnostic Computerized Adaptive Testing

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiaojian Sun ◽  
Yanlou Liu ◽  
Tao Xin ◽  
Naiqing Song
Keyword(s):  
Adverse Effects ◽  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Adaptive Testing ◽  
Unified Model ◽  
Variable Length ◽  
Calibration Error ◽  
Test Length ◽  
Test Efficiency ◽  
Item Parameters

Calibration errors are inevitable and should not be ignored during the estimation of item parameters. Items with calibration error can affect the measurement results of tests. One of the purposes of the current study is to investigate the impacts of the calibration errors during the estimation of item parameters on the measurement accuracy, average test length, and test efficiency for variable-length cognitive diagnostic computerized adaptive testing. The other purpose is to examine the methods for reducing the adverse effects of calibration errors. Simulation results show that (1) calibration error has negative effect on the measurement accuracy for the deterministic input, noisy “and” gate (DINA) model, and the reduced reparameterized unified model; (2) the average test lengths is shorter, and the test efficiency is overestimated for items with calibration errors; (3) the compensatory reparameterized unified model (CRUM) is less affected by the calibration errors, and the classification accuracy, average test length, and test efficiency are slightly stable in the CRUM framework; (4) methods such as improving the quality of items, using large calibration sample to calibrate the parameters of items, as well as using cross-validation method can reduce the adverse effects of calibration errors on CD-CAT.

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