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# Nerd Alert: Checking My Work

### Jack Moore

Jack Moore is a freelance sports writer based in Minneapolis who appears regularly at VICE Sports, The Guardian and Baseball Prospectus Milwaukee, among others. Follow him on Twitter @jh_moore.

Back in the final week of February, I took a look at how often NBA players were getting their shots off at the rim. Because there is undoubtedly a little bit of luck in shooting a basketball - these mechanical acts are only so repeatable by human minds and bodies - it's better to look at something the player does control: where he takes the shot. Or, at least, so the theory goes.

It's tough enough to predict what will open over a full season. Limit your scope to one-half of a season and allow a few random acts to play a much bigger role and the task becomes even tougher. But that is essentially what this analysis attempted to do.

Overall, the data did a decent job. Although I didn't exactly present the data in this form, the suggestion was that we can project field goal percentage for the rest of the season given last season's field goal percentage and the change in the player's at-rim shot rate. The formula the data gives is as follows:

Expected FG percent = [Last Year's FG percent] + 0.237*[Difference In At-Rim Rate] – 0.008

And it turns out this does a reasonable job of predicting field goal percentage, with a coefficient of determination of .575 – that is, 57.5 percent of the variation in second-half field goal percentage is explained by these two variables.

So I wasn't selling you snake oil, at least. But here's the real question: is this really an improvement over the basics? Is it better than shooting percentage at midseason? What about last year's shooting percentage?