Expected Points Gained, A Framework For Evaluating Actions On A Basketball Court

What is more valuable, an offensive rebound or a defensive rebound? Consult Expected Points Gained.

The currency of a basketball game is points.  This is obvious.  After all, this is the one thing we add up to determine who won and who lost.

This really simple insight actually has a lot of value as a framework for evaluating everything that happens on the court.  Each action that a player takes, be it good or bad, has to have its effect traced back to the scoreboard to be properly measured.  Of course, some actions, like made jumpers and rebounds, are neatly recorded in the box-score and others, like contesting a shot or moving the ball quickly to keep an offensive action going, are not.  But, at the end of the day, we really need to tie everything back to points.

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3 Random NBA Questions (10/15/18): What is the Probability that the Lakers Miss the Playoffs?

Q1: What is the probability that the Lakers miss the playoffs?

Inspired by Ben Falk’s Predict challenge on his website, Cleaning the Glass, (a really cool website if you’re an NBA fan) and filled with intrigue about year 1 of the LeBron led Lakers experiment, I decided to tackle this question.

So, how should we go about answering it?

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Did the 76ers Really Gain 2.3 Points of Net Rating from Poor Opponent Outside Shooting in 2017-18?

Defending the jump shot, particularly the 3-point shot, is one of those seemingly small topics that for some reason I keep coming back to.  I think what first peeked my interest was a podcast in which a guest speculated that one of the biggest unanswered questions in basketball analytics was the degree of control the defense has on the offense’s 3-point field goal percentage.  He said that some analysts guessed that much of the year-to-year variability in 3-point percentage defense was due to chance.  The main source of control a defense has with to respect to 3-pointers could be limiting the number of attempts (particularly open and corner threes), rather than forcing a low percentage.

I dived right into some small projects inspired by this discussion.  My first post examined whether the shooting ability of the players actually taking the 3-pointers against a particular defense had some ability to explain variability in 3-point percentage defense.  I looked into whether the Celtics’ sustained run of top-5 3-point percentage defenses under Coach Brad Stevens could be a fluke of randomness (it’s highly likely it’s not).  I also analyzed which team statistics were most likely to carry over from the first half of the regular season to the second, and found defensive 3-point percentage was low on that list.

Now, I have tried quantify exactly how many points of defensive rating (points per 100 possessions allowed) are subject to opponent shooting variability.  Besides simply considering 3-pointers, I also looked at free throws and ‘deep’ 2-point attempts, where I defined deep as greater than 16 feet.

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Threes and Layups NFL Team Ratings, Explained

With the 2018 NFL season underway, I decided to release some work on my first NFL project: a team rating and prediction system.

Go to Ratings

Go to Weekly Picks

Motivating this project was a simple question.  How much should we adjust our thinking about a team based on the result of 1 game?  This has always been a question which has intrigued me.

We go into a new football season with some general expectations of the ability level of each team.  Many of our expectations come from their past performance, but some new information is also added with offseason signings, trades, injuries, etc…  Of course, there is a lot of uncertainty surrounding each team.

Then we witness week 1!  Some teams look like underrated breakout candidates, and others flop.  Hot takes abound.  But how much information can 1 game really give us?

How The Rating System Works

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Which Types of NBA Teams are the Best Win Total Over/Under Bets?

Though the NBA regular season is still 43 days away, it’s never too early to take a look at regular season win total over/unders! 

Rather than building a projection system and delving into whether specific teams are more likely to go over or under, I instead decided to determine whether or not five key predictors could in any way help us make predictions in general.  I will introduce the specific predictors in the next section.

To conduct my analysis, I looked at the over-under lines for all teams over the past six regular seasons.  I was able to find a combination of lines from Bovada and the Westgate SuperBook, using the articles cited in the reference section.  The dates for these lines ranged from October 5th to October 18, so they generally were recorded a week or two before the start of the regular season.  All other information used in this article, mainly the statistics used to calculate my predictors, came from basketball-reference.com.

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Democrats have a 23% Chance of Having a Majority on the Supreme Court in 2028

The retirement of Justice Anthony Kennedy and nomination of conservative Brett Kavanaugh to replace him is poised to give Republicans a more reliable majority on the Supreme Court.  But a 5-4 majority is a narrow one.  A Democratic victory in the 2020 presidential election coupled with the death of a single Republican appointed justice would produce a reversal in power on the Court.  The current state begs the question: precisely how likely are Democrats to regain the majority?

Despite the complexities of the legal and political processes that produce Supreme Court candidates, this question is surprisingly approachable statistically.  The central variables involved are not from the domain of legal theory or constitutional interpretation, but rather from areas familiar to a statistician: life expectancy, behavioral preferences, and election projection.  By consulting actuarial tables, the record on judicial retirements, and the history of presidential election results, I have endeavored to construct a quantitative understanding of the likelihood of changes of control on the Supreme Court.

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Which College Statistics Are Most Correlated With NBA Success?

The NBA draft is almost upon us! For the sake of curiosity, I decided to dig into the data to determine which college statistics have been most correlated with NBA success.

I will first give a few words on my methodology. I considered all players drafted in the year 2000 to the present whose age 25 season could have happened in 2017-18 or earlier. The age 25 season criteria is included because I measured player value in terms of Win Shares (a stat provided by basketball-reference) produced in the age 25 season. I chose to measure performance at this age rather than something like prime years (age 26-29) to allow more recent draft picks into the sample.

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