Test scores are more than 20% higher in elementary schools where library media staffing is at 80 hours per week or more than in schools with less than 60 hours per week.
Elementary School library
Students tend to perform better on achievement tests where school libraries have: More full-time equivalents (FTEs) of staffing; Larger collections of periodicals and instructional videos; Better-networked online resources made accessible via computers in the library as well as in classrooms, lab, and offices; Higher total library expenditures; and Heavier use, as indicated by both library visits and circulation. (p. 11)
Elementary schools with at least one full-time endorsed librarian averaged better [Colorado Student Assessment Program] CSAP performance than those with less than one full-time endorsed librarian. (p. ii)