The phi coefficient and chi square as indices of item validity

Two new methods of item analysis are described. One involves the computation of the coefficient (correlation of a fourfold point distribution) and the other involves chi square. The only data required are the proportions of passing individuals in the upper and lower criterion groups, for the determination of , and in addition,N, for the determination of chi square. Abacs are presented for graphic solution of the two indices of validity, and tests of significance are provided.