Universities, think tanks, nonprofits, policy institutes, and the government conduct policy research to inform decision-making at all levels of the education system.
You can use SuperSearch to locate policy briefs and reports, often labeled with the Report icon.
The Institute of Education Sciences (IES) is the statistics, research, and evaluation arm of the U.S. Department of Education. It has four subdivisions: NCER, NCES, NCEE and NCSER. While a lot of IES research appears in SuperSearch, you can also search these websites directly:
Not all aspects of education can be measured quantitatively-- but some can! Raw statistics and data are useful for providing district- or state-level context on a problem, like when writing your problem statement in Chapter 1.
The National Center for Education Statistics (linked above) provides valuable insight and reports, but you might want to explore more local sources of data, too. To find your district's data center, Google [your school district's name] + data.