This conceptual design of a model of staff differentiation is divided into a staffing sub-model and an implementation sub-model. The design enables a school system leadership to provide its component schools with the means for implementing a staff differentiation model designed for the individual school. The staffing sub-model is designed to organize the instructional staff into a logical vertical and horizontal differentiation. The five vertical levels of professional personnel are consulting teacher, directing teacher, staff teacher, instructor, and resident intern, assisted by paraprofessional personnel including instructional assistants, aides, student assistants, lay adjunct teachers, and volunteer assistants. The horizontal differentiation has four broad function areas: instruction, staff development, administration, and planning-research-evaluation-reporting. The implementation includes 1) a process for the allocation of total staff units to each school, 2) the division of all schools into seven classifications according to size and type, 3) an assignment of unit values to each position in the vertical hierarchy of the staffing sub-model, 4) a procedure for determining the approximate recommended number of each job classification needed at a particular school, 5) a set of charts from which job specifications may be collated for each staff member, and 6) the general criteria by which the staff is held accountable for performance. (MBM)