Professional organizations can provide formulas.
For example, one-half of one percent of a district's total budget is a starting point, provided funds are not used for substitute teachers. Because time is a precious commodity, teachers are reluctant to be away from their classrooms. Some school board members and parents react negatively to staff development absences. Therefore, different structures of schooling should be explored to provide time for, and more appropriate timing of, staff development. Again, many national reports from respected organizations offer recommendations regarding time allocated for staff development.