Although formula scoring has been used since the early 1900s, it was not until 1975 that Frederic Lord offered the following potential psychometric justification for its use: If under formula-scoring directions an examinee omits only those items which would result in completely random guesses under number-right scoring directions, then the formula score will be a more efficient estimator of the examinee's standing on the trait measured. Whenever the number of omissions is greater than zero, the formula score will be more reliable than the number-right score.

The purpose of this study was to test the premise that examinees omit only those items for which they have no knowledge when taking a test under formula-scoring directions. Several studies had been carried out previously to test this premise, and the design used in this study was a synthesis of the previous designs.

Included in this study was an investigation of examinees' responses, under formula-scoring directions, to items that were constructed to be obscure. Also examinees responded to questions about their attitudes towards formula-scored tests and their strategies when taking formula-scored tests.

Because of the results of the test of Lord's premise, also included in this study was a further investigation of omissiveness, the tendency to omit items under formula-scoring directions. Item difficulty and item omissions were examined relative to Lord's premise. A variable, called L for convenience, was computed for each item in order to find to what extent responses to test items support Lord's premise. Finally, the possibility of misinformation producing a counter effect to inappropriate omissions relative to Lord's premise was investigated.