Statistical estimates of the future of the 2023-24 Detroit Pistons redux
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A couple of days ago, I made a superficial and inevitably amateurish attempt to disentangle the extent to which the Detroit Pistons’s record-breaking futility this season has been a function of their legitimate terribleness, and how much has been just bad luck.
Andrew Gelman has now done a deep deep dive into this same question, and produced, predictably, a far richer analysis of the same question.
One thing Gelman delves into until reaching mithril-lode depths is the extent to which points scored, points allowed, and the ratio between them might help unpack the extent to which an NBA team’s won-loss record is a reflection of its true quality, as opposed to other factors. Go read his analysis if you’re interested in basketball, statistical analysis, or especially both subjects.
A side note: Those who are familiar with Bill James’s Pythagorean Theorem will recognize the basic method, although Gelman’s analysis is quite a bit more complex than James’s (which is not to say that James’s method is unsound). What James discovered was that the ratio of the square of a team’s runs scored and the square of its runs allowed tended to be a good proxy for the team’s winning percentage. What was particularly interesting about this is that a team’s Pythagorean record — that is the winning percentage implied by this method — was a better predictor going forward of its record than its actual won-loss record. What squaring the ratio of runs scored and allowed does, apparently, is help shake out the extent to which a team’s record is a function of quality as opposed to luck.
Gelman suggests NBA scoring ratios may also be better predictors going forward than won-loss record, which makes sense intuitively, although he’s cautious about drawing any firm conclusions, given the limitations of the data.
Meanwhile last night the Pistons lost in overtime on the road to the best team in the league, thus extending their infamy for at least a couple of more nights. (Another interesting question is the extent to which other teams will now be extra motivated not to be the team that allows Detroit to snap its history-making streak).
In any case, please use all the information in Gelman’s post to gamble responsibly, unless you would like the gambling industry to make money