A school filled with wealthy families will always have solid readiness and test scores, just because the families can afford whatever help is needed. A quality school wouldn't just let underprivileged children slip through.
I agree with you that this is important on a societal level, but making such a vague, contentious, and poorly defined input, which individual schools have a questionable ability to influence, 33% of a school's overall rating is nonsensical.
Imagine a school with a 10 for equity, but a 6 for test scores and 5 for college readiness. It will get the same 7 rating as Berkeley High. Which would you rather send your kids to?
Imagine a school with a 10 for equity, but a 6 for test scores and 5 for college readiness. It will get the same 7 rating as Berkeley High. Which would you rather send your kids to?