Speech Sounds Perception Test: nonrandom response locations form a logical fallacy in structure.

The response format of the Speech Sounds Perception Test confounds speech perception with irrelevant method variance. To rectify this problem the response format was revised by randomizing the response locations. An empirical comparison of the revised and original forms was undertaken with forensic (n=59) and psychiatric (n=67) samples. The empirical results coupled with the logical problem in the original form indicates that a revision is necessary.