Anonymous wrote:I think you are also simplifying the percentile correlation. The DC-CAS proficient range is just that--a range, with the highest scores just points below the cutoff for the advanced range. Perhaps the lowest scores in that range correspond to the 16th percentile nationwide, but not the entire level.
No. Since the admissions process uses the test results as a cutoff, it's exactly the right comparison. To be eligible to take the SWW admissions test, you have to score either proficient on the DC-CAS, or 150 combined on the PSAT. Scoring proficient on the DC-CAS means scoring at the 16th percentile or above. Since the PSAT has three parts it's a little tricky to do a direct comparison, but if you score 50-50-50 it puts you in the 74th, 72nd, and 82nd precentiles for the three sections. If you score 50-52-48 it puts you at 74-78-75. That's a huge difference.
Note also that the DC-CAS percentiles are for 8th graders and the PSAT percentiles are for 10th graders.
Clearly, there are tons of kids -- like 60% of the population -- who would be admitted using the DC-CAS but not using the PSAT.