Kuder-Richardson 20 refers to a formula for estimating the internal consistency of a test. The KR20 or KR20 method is equivalent to the average split-half correlation obtained from all possible splits of the items. For the KR20 formula to be applied, all items must be scored either 0 or 1.
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