https://news.ycombinator.com/item?id=21641360
sounded familiar, turns out I had read that it didn't replicate (surprise) within the past week on hn
As with most psych studies, there's probably a grain of truth -- of course investing in people tends to make them more successful, but it's not simple magic tricks.
Also I never used the word "smart" once in the article. I talk about learning behavior and work performance instead.