Public library expenditures and reading scores research

 A study of US public libraries found that library capital investments increases children's attendance at library events 18%, their checkouts by 21%, and visits by 21%. It translated into improve test scores in nearby school districts. A $1000+ per-student capital investment in local public libraries increased reading test scores the .02 standard deviations (not significant for math scores. 

Gilpin, G., Karger, E., & Nencka, F. (2021). The returns to public library investment. Federal Reserach Bank of Chicago. 

https://www.edworkingpapers.com/sites/default/files/ai21-386.pdf

Outside Factors for Student Success Report

High-school graduation rates are trending upward, and prekindergarten enrollment and eighth-grade math proficiency have remained steady, according to a 2019 report. The report also examines how socioeconomic factors, health, family and community issues affect outcomes for students. For example, among children in low-income homes, 78% of 4th-graders score below the proficient level in reading, compared to 48% of children in moderate- and high-income families.
2019 Kids Count Data Book. Baltimore, MD: Annie E. Casey Foundation.
https://www.aecf.org/m/databook/aecf-2019kidscountdatabook-embargoed.pdf