**Kuder-Richardson formula 20**refers to a formula for computing split-half reliability that corrects for the fact that individual scores are based on only half of the total test items; a statistic used to determine internal reliability of tests that use items with dichotomous answers (yes/no, true/ false). Kuder-Richardson formula 20 is also known as Kuder-Richardson 20 , KR20 or KR20 method . Please see also Kuder-Richardson 20