Jessica Kerr wrote a very interesting post on bell curves and engineering teams. Jessica’s point is that bell curves are for random distributions, and that when teams share information and learn from each other, they no longer can be modeled by a random distribution. I think this as true, and a valuable insight. It reminded me of a different, related observation about teams and bell curves. Back in the 1980s, when he was applying analytics to baseball teams, Bill James argued that a common feature of the decisions made by poorly performing organizations was the assumption that baseball talent was normally distributed and could be modeled with a bell curve.
I’ve now tried to write this post like three times, and one thing that’s clear to me again is why you don’t see more write-ups of even moderately complicated real-ish problems. It’s hard to get enough of the context across to make the code sensible without being overwhelming. But there’s a Rails and ActiveRecord structure that this example gets to that I think is useful, so I’m going to try again.