Computerized adaptive testing
A computer-adaptive test (CAT) is a form of test that adapts to the testee's ability level. The level of questions the test taker is presented are determined by his performance on previous problems. For example, if a testee performs well on a set of intermediate questions, he will then be presented with more advanced questions. If he performs poorly, he will be presented with simpler questions. Compared to static multiple choice tests, computer-adaptive tests require fewer test items to arrive at a more accurate estimate of a testee's proficiency.
The GRE General Test is currently primarily administered as a computer-adaptive test.