‘Students score an average of 10-20 % higher on reading and achievement tests when their school has a strong library media program. This effect holds, regardless of other school conditions such as student-teacher ratio, overall per-pupil spending, student demographics, and community socio-economic conditions.’

Source: Gretes, Francis. “School Library Impact Studies: A Review of Findings and Guide to Sources”. Gretes Research Services.  2013. pg 5.