Properties of the item score matrix

A method of deriving from the item score matrix all the usual statistics describing the performance on a test of a group of examinees is given. Since this matrix usually is not actually written out, but is implicit in a set of punched cards, a method of working from a more compact matrixF is described. A numerical example is presented. Applications and advantages of the method are cited, as compared with that of recording only the examinees' test scores and the item difficulties.