The principle of supply and demand has been chosen to capture and present quantitatively an important data source for describing employment potential. The Pennsylvania State Occupational Information Coordinating Committee has developed an Occupational Information System (OIS) and companion microcomputer version (Micro-OIS). This system contains data on the demand for workers (a prediction of annual anticipated job openings for specific occupations) and supply of workers (actual data from completers of formal training programs). To use this information, educational planners need to understand the structure of the published data. Program planning starts with an inventory of students. The educational planner can then take an inventory of the universe of occupations including the employers who provide the work. This occupational inventory of local employment options must include specific information on employers, recruitment methods, worker skills, and the way to learn these skills. Finally, the planner needs to take an inventory of the universe of educational programs including resources available to be committed to educational programs. (Checklists are provided to aid the planner in deciding when to establish a new vocational program or terminate an existing one.) (YLB)