I got down to the point where it said "we measured attitude, then called it effort," and threw up my hands. Without paying for the full article, I can't tell whether the researchers actually did a reasonable job, though.
The "parental effort" they looked at (according to the synopsis) was:
- did you read to your kids
- did you go to parent-teacher conferences
- does your kid's teacher think you care
There's no indication here that any other sort of effort has value, because that's not what the study was designed to do.
Plus they were looking at kids who graduated from UK schools ~30 years ago, and it's not clear how much you can extrapolate from that.
OTOH, the conclusion of "if parents have high expectations for both kids and schools, the kid is likely to get a better outcome" is not one I personally disagree with.
