About the ability estimation algorithm optimization of IRT-based Computerized Adaptive Testing system

Aiming at the problem of Newton_Raphson algorithm calculation model for the ability estimate on the basis of the Item Response Theory (IRT) and the problem of lack of corresponding coordinating strategy when the calculating model has no root or many roots, Logistic median algorithm model and relevant coordinating strategy is put forward, compared and analyzed. Simulated experiments are conducted with the research object of three parameter logistic adaptive median algorithm model. The result shows that this Computerized Adaptive Testing (CAT) system has more superior function and lower calculation quantity, with fast convergence and the accuracy of ability estimate.