This research brief examines staffing patterns within U.S. public school systems. Specifically, it answers the following sets of questions: (1) Why is information about staffing ratios important? (2) How many people currently work in public schools? What proportion of these are teachers, administrators, and support staff? (3) What are the current staffing patterns in public school systems? Do they vary by district enrollment size and per-pupil expenditure level? and (4) How have staffing patterns changed over the years, particularly for teachers and central-office administrators? To provide the answers to these questions, the following data are presented through narrative, graphs, charts, and tables: student/staff and teacher/staff ratios for individual positions and for aggregate categories of professional personnel for the 2002-03 school year; trend information of student/staff and teacher/staff ratios for the school years covering 1992-93 to 2002-03; and data from the Educational Research Service (ERS) National Survey of School District Budgets and the National Center for Education Statistics. Included are brief descriptions of related resources available from ERS. (WFA)