Computerized Adaptive Testing — Item Response Theory Simulator

Modern computerized tests don't ask every candidate the same fixed list of questions — they pick each next question in real time, choosing whichever item will reveal the most about the test-taker given what's been learned so far. This simulator renders a 50-item bank spread across a 3D difficulty landscape and runs a genuine computerized adaptive test against it: every item follows the two-parameter logistic IRT model, the engine re-estimates the examinee's ability with a Newton-Raphson maximum-likelihood update after each response, and the maximum-information selection rule steers the next question toward the difficulty level that will shrink the standard error fastest. Set the hidden true ability, switch between adaptive and random item selection to see the difference in efficiency, and watch the green ability marker converge on the examinee's real position along the difficulty axis.