A company to develop a new procedure for use in selecting sales personnel approached a consulting psychologist. The company wanted the new procedure to replace a non-validated, off-the-shelf sales aptitude instrument it was in using. This test had been developed by a human resources executive and was based upon its author’s theory of there being a relationship between biorhythms, among other factors it purported to measure, and sales success. There was no empirical research to support this theory, it had not been validated at the employment site, and the author could provide no validation or other research that had been performed on the selection device.