Although the RCTs are no longer used to measure readiness to graduate, this fact alone does not disqualify them as a measure of whether students have received a sound basic education. Nevertheless, as both parties agree, the RCTs assess achievement at only an eighth or ninth grade level in reading and a sixth-to-eighth grade level in math. Thus, while passing the RCTs may show that students have received a sound basic education as defined by the Appellate Division, it does not prove that they have received a meaningful high school education, as the trial court concluded (187 Misc 2d at 61). Additionally, according to the 655 Report for 1999, City students who took the RCTs in 1997-98 actually passed at a much lower rate than 90 percent; 51 percent passed in math and 72 percent in English. The Report explains that City schools had adopted a new policy of administering the examinations to ninth rather than 11th graders, and this may account for some of the difference. Since the exams are a diagnostic tool for measuring skills taught in middle school, these results, at most, cast doubt on the results middle schools accomplish, rather than proving that students have received a meaningful high school education. Further, the 1997-98 11th grade class with the 90 percent qualification rates consisted of only about 40,000 students, compared to a 9th grade enrollment of over 90,000. Thus the State's RCT passage rates -- aside from proving nothing about high school achievement -- would surely be lower, but for the alarming number of students who fall behind or drop out and so do not take the exam. This fact illustrates the need to be cautious in relying on test results, a point we made in CFE even as we recognized that such results have some value (86 2 at 317). The trial court properly exercised such caution in its discussion of test results, noting that the failure of many students to be promoted diminishes the value of evidence that students test at grade level (187 Misc 2d at 67). Apart from the RCTs, the State relies on results from an assortment of commercially-available nationally-normed reading and math tests administered to children in City elementary schools, notably the CTB-Reading (CTB-R) and California Achievement Test (CAT). As the State points out, just under half of all City schoolchildren score at or above the 50th percentile in reading, and a larger number do so in math. Plaintiffs counter that these exams are "norm-referenced" -- they present information only on how students perform relative to other students -- in contrast to "criterion-referenced" exams, which are informative about how students master content they are expected to know at a given level. Further, plaintiffs argue that