The National Center for the Study of Privatization in Education at Teachers College, Columbia University is a repository of useful information and research reports on the subjects of privatization, charter schools, vouchers, choice, homeschooling, etc. They provide crisp definitions and background briefing on these topics plus 133 (and counting) research reports. For example, the two recent reports discuss how parents make choices and school choices among public, private, or homeschooling.
They also include Policy Briefings, Book Reviews, FAQs, Hot Topics and other helpful information. This is a valuable resource you will want to bookmark.