The article deals with the application of Fischer’s index of exaction to the assessment of didactic test performance. The substance of the method consists in each test item having a measuring index in the form of a number of marks fixed by a group of experts. For the sake of greater objectivity it is possible for the assessment to include also the frequency of errors in individual items of the test. Final assessment is expressed by the total number of marks attained, and this total can — in case there is a set time limit for the test to be handed in — be multiplied by a special coefficient.