A test system realizes in an English ability test, etc. not only binary correct-false evaluation but also a partial score. The test system uses a computer (101, 102) including an input/output device (207, 208) and a network (103) such as the Internet, etc., and uses a partial test score model obtained by amending the conventional Item Response Theory in estimating an item parameter and ability. In the partial test score model, a partial score is assumed to be a true-false average of a plurality of items having the same parameters. Using the test system of the present invention, a test of the presentation format which is hard to determine the correct or wrong answer such as writing and speaking tests in a foreign language test, etc. can be more easily controlled than in the conventional system.