Somewhat against the point I made earlier, and in favour of "ability to benefit from test prep is itself g loaded" anyone who didn't follow The Perfect Score Project the first time round might like to read up on it:
http://perfectscoreproject.com/about-the-perfect-score-project-2/
This professionally competent woman devoted a year, essentially, to prepping to a perfect SAT score. I assumed she'd do it, and I think she assumed she'd do it. She didn't; her maths scores moved remarkably little. Tbh I still can't really absorb this, and tend to wish I'd had the chance to prep her myself!

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