EQUATING TEST SCORES – THE MAXIMUM LIKELIHOOD SOLUTION FOR A COMMON EQUATING PROBLEM

The maximum likelihood solution is presented for the following equating problem: Two tests, U and V, are to be equated, making use of a third “anchor” test, W. The examinees are divided into two random halves, which will be called the “a‐group” and the “b‐group.” Tests U and W are administered to the a‐group; tests V and W are administered to the b‐group. It is assumed that any practice effect or other effect, exerted by U and V on W, is the same for U and for V. The solution obtained differs from that introduced at ETS by L. R Tucker only in the initial assumptions from which it is derived.