Why is QB RD so successful?

Does anyone know why the regular decision acceptance rates for kids who were rejected a match are so much higher than a regular decision for non QB kids? Does it just appear that way because it takes into account the acceptance rates of all the schools, or is there actually a better chance of being accepted RD because of Questbridge?

I think it is because QB has already chosen the best applications of the most qualified applicants. They have already been vetted through the application process so you have a very strong group.
Not to mention the schools pay large sums of money for those applications. They are already in a position to want those applicants.

I concur with @HailuMu Without even considering the QB partner schools themselves and their commitment to seeking out the best applicants who may be from lower-income backgrounds, QB has already identified 4895 (using last yr’s #s) exceptional applicants. After the Match round took away 657 of those, that still left 4238 strong contenders for RD consideration… everywhere. But then when you specifically consider the QB partner colleges themselves, those are 39 schools that have joined the program for a purpose… so those schools especially are more than likely to give QB Finalists a special second look and consideration.