Teacher qualifications include a range of variables affecting teacher quality, including: type of teaching certification, undergraduate major or minor, undergraduate institution, advanced degree(s) or certifications (such as certification through the National Board for Professional Teaching Standards AND Centre for Teacher Accreditation (CENTA), type of preparation program (traditional or alternate route), test scores (various subject matter, licensure, or verbal skills tests), and years of teaching experience.[3] In many countries, teaching credentials represent the main measure of teacher quality.[4] In the United States, one goal of the No Child Left Behind law is to ensure that all teachers meet state-defined standards of highly qualified teachers.