The National Center for Education Statistics (NCES) is a federal entity for collecting and analyzing data related to education. A range of online tables and figures are available with country comparisons under the categories of attainment, enrolment, financial/expenditures, subject proficiencies, post-secondary education, and school system characteristics. There are a range of data tools available including: a data analysis system, an educational data analysis tool, national assessment and educational program (NAEP) data explorer, plus links to surveys and programs.
Questionnaire item banks are available online.
Freely available data on internet.