A few posters have complained that their children's high schools do not allow students to take AP classes before 11th grade, even if they are ready. A College Board report "The relationship between PSAT/NMSQT scores and AP examination grades: A follow-up study"
http://professionals.collegeboard.com/profdownload/pdf/06898CBR06-1.pdf finds that PSAT scores are highly correlated (typically about 0.5-0.6) with AP exam scores. Table 9 shows that 94.0% of students with math PSAT score of 71 to 75 get at least a 3 on AP Calculus AB, and 96.4% of students scoring 76 to 80 on the PSAT-M do so. Table 13 shows how composite math+verbal+writing PSAT scores predict scores on AP exams in the social sciences. Table 3 shows that 10th and 11th graders do about the same on AP tests, controlling for PSAT score.
SAT scores are equivalent to PSAT scores multiplied by 10. Students in 10th grade and earlier should be allowed in AP classes if they have high PSAT or SAT scores, and parents can reference this study to advocate for this.
