Results of over 25 attempts to count untreated cases of psychological disorder in community populations are reviewed, and the problem of validity in the measures of disorder is analyzed. Evidence of validity is found to be scant. The position is taken that, with no generally accepted criteria available, and no universe of content agreed upon, construct validity takes on added importance. A lead to 1 possible nomological net for the construct of psychological disorder is the consistent finding that the lowest socioeconomic stratum has the highest rate of symptomatology. This lead is developed with reference to the transience of symptomatology found in extreme situations, in contrast to the persistence of symptomatology observed in patients and in studies of experimental neurosis.