I found this via Library Lines:
Oklahoma Association of School Library Media Specialists Time Task Study
Premise: A decade of research, starting with Dr. Keith Lance’s well-known “Colorado II Study,” has shown that quality library media programs contribute to academic achievement and student success.1 Many school libraries, however, remain so understaffed that they fail to achieve their potential to impact student learning. Staff reductions and program elimination, we believe, is often due to a lack of understanding of what professional librarians do. Successful school librarians support teaching and learning while they manage the day-to-day operations of the library media center when they have the assistance of clerical staff. This study sought to clarify the various roles of professional librarians and show how much time is contributed to each in a nominally staffed library that includes one or more professionals and one or more library assistants.
Goals: The study had four goals:
Identify and organize descriptors of school library media roles and specific tasks. Measure the amount of professional and clerical time needed on specific tasks to provide quality services. Determine the balance and relationship between “professional time” and “clerical time” spent in quality library media programs. Develop a baseline profile of a school library media specialist and assistant for communication and reflective practice purposes. The results may also provide a piece of a rationale to support full staffing of school library media programs.
A rather quick 10 page read with lots a graphs. Actually there's a lot of information in it academic and public librarians could use as well.