I think you’ve missed the best existing study on this question which is Glewwe et al using longitudinal panel data to track kids through to adulthood and look observationally at the wage gains from better early test scores https://www.sciencedirect.com/science/article/abs/pii/S0167268121004947. They find 13% higher earnings from 1 SD better scores.
Interesting stuff. At CGD we’re hoping to follow-up with some old RCTs to find the ideal evidence on this question—what actually happened to incomes of people who have experimentally induced higher early grade test scores: https://www.cgdev.org/blog/will-raising-test-scores-developing-countries-produce-more-health-wealth-and-happiness-later
I think you’ve missed the best existing study on this question which is Glewwe et al using longitudinal panel data to track kids through to adulthood and look observationally at the wage gains from better early test scores https://www.sciencedirect.com/science/article/abs/pii/S0167268121004947. They find 13% higher earnings from 1 SD better scores.