The Food and Drug Administration (FDA) advises sponsors of new drugs to classify human subjects on the basis of four specific demographic categories-age, race, sex, and weight. The FDA provides no advice for other possible categories, such as hand edness. Sponsors' collection of data on race (a model requisite category) is seldom overridingly important, however, and sponsors' inattention to handedness (a model neglected category) can be very wasteful. For some drugs and some trials, an array of demographic characteristics other than those identified in the FDA Guideline should be analyzed.