Ah yes, I was thinking this morning that the article's interpretation of the study results was leaving out this selection effect.
The study, by itself, doesn't tell us whether hiring low digit ratio traders would be more profitable for a firm, or even if the average lifetime earnings of someone entering the trading profession would be higher for someone with a low digit ratio.
The study, by itself, doesn't tell us whether hiring low digit ratio traders would be more profitable for a firm, or even if the average lifetime earnings of someone entering the trading profession would be higher for someone with a low digit ratio.