Dr. Thomas is a professor emeritus of evaluation and research methodology and Dr. Collier is a professor emerita of bilingual/multicultural/ESL education, both from George Mason University. Together they bring clear research findings to countries around the world. After having analyzed over 6.2 million student records from all regions of the United States, their research findings are very generalizable to all regions and contexts of the U.S. In addition, according to researchers from Africa, Asia, Latin America, Europe, Canada, Australia, and New Zealand, the Thomas & Collier research studies have been replicated in other contexts and have been found to be very generalizable to many other countries for educational policy making.