The experimental development of occupational classifications based on regularities of movement of workers among jobs has been used recently to place job seekers in available jobs. The social and psychological meaning of a classification, developed by Dauffenbach, was explored by describing the classification's categories in terms of the demographic characteristics of category incumbents (based on data from the 1970 census) and job content (based on the Dictionary of Occupational Titles and Position Analysis Questionnaire data). Results imply that mobility-based classifications: (1) provide powerful descriptions of the structure of labor markets; (2) are related to job content; and (3) are also related to sex and race, well beyond the extent to which this association is shared with job characteristics. Findings suggest that basing a classification for personnel placement on occupatonal mobility patterns may incorporate undesirable aspects of existing labor market practices, and that more direct efforts aimed at systematizing knowledge about the transferability of skills may be more productive than relying on mobility-based classifications, despite the heuristic value of the mobility approach. (Author)