Basketball Predictions – How’d It Go?

Here’s the post on methodology I used for assessing tournament teams this year.

How’d it do?

First round: pretty good!  27/32 (84%).  I had a lot of these games as outright winners and very few coinflip games.  I thought my approach for picking coin flip games was pretty basic, that is, if a team’s upper bound was over their opponent’s mean, then I picked by flipping a coin.

2nd round: 9/16 (56%).  Yeesh.  I got more and more coinflip games as the tournament went on, but even some that I had as outright winners didn’t go the way I projected.  It’s logical if you think about it though.

Take, for instance, Duke and FSU.  Both teams had been erratic all season, laying occasional stinkers.

FSU got absolutely stomped by Xavier, with Xavier shooting .657 true shooting for the game.  Among the best teams in college basketball, that was .04 better than the best shooting team in the country (UCLA).  Scorching.  FSU meanwhile laid a dud (.433 TS).

Duke’s achilles heel all season has been Grayson Allen, though he is occasionally brilliant.  The problem with Grayson is that he’s trick or treat, he’s either executing and hitting shots or he’s dribbling the ball off his feet and throwing it into the stands.  They had 18 turnovers last night (nearly 1 per 2 minutes or approximately 1 per 3 possessions), which led to South Carolina taking 10 more shots than them over the course of the game.

This leads me to the biggest limitation in my model.  I don’t think I included enough variance.  The reality is that these teams aren’t all that different, outside of a few really good ones and a few really bad ones.  There’s a lot of in the middle and when you combine a fairly short game and a one and done model, you’re going to get some bizarre stuff.

Let’s take as an example the NBA playoffs from 2016.  There were 15 series, 2 of which were sweeps.  Of the other 13, 3 were 4-1.  That means of 15 series, 10 of them (2/3 or 66%) were at least 4-2!

Let’s look at just the Cavs series with Golden State.  The series ended 4-3 and the margins were 15, 33, 30, 11, 15, 14, and 4 points.  The average margin was 17 points!  That’s why it gets complicated when you say that one team beating another one badly on a given day means they’re better.  Particularly in small samples, there’s just a lot of variance in a game that can be decided by a couple errant passes or bad bounces, and playing these games with college freshmen that have been playing together for about 15 minutes can only increase the variance.

In conclusion, my picked champ, Duke, lost in the 2nd round, but I can take some solace that Vegas picked the same champ.  Even Vegas doesn’t know!  It’s just a coin flip when it comes down to it.  The house (and the field) always wins.


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