In Boston again for the Sloan Sports Conference this weekend

We are now in Boston for our fifth MIT Sloan Sports Analytics Conference that takes place Friday and Saturday.  Although we’ve been fairly quiet on Twitter this season (and on this site), we’ve been busier than ever!  We also recently contributed to a story a major analytics site should be publishing in the next week or two, so we’ll let you know when that story gets published.

If you’re in Boston for the conference and would like to chat about the latest on NBA referee analytics, feel free to ping us on Twitter (@RefAnalytics) and let’s try to connect in person.

In the meantime, checkout these pics we took near the convention center of Boston’s epic snow!

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Details on a large increase in 3-point shooting fouls during these playoffs (not necessarily a bad thing)

Long before last night when Chris Paul fouled Russell Westbrook on that 3-point shot with 6 seconds remaining that helped the Thunder cap off a big comeback, there was lots of chatter the past couple of weeks about the seemingly inordinate number of shooting fouls on 3-point attempts (and “4-point plays”) in this year’s playoffs.

We decided to look into this further, get more concrete numbers, and compare the numbers to the same point in last year’s playoffs. The difference is startling. We also went a step further and identified names of shooters and referees involved to provide further context.

A huge increase

In the 68 playoff games played through Tuesday, March 13th, NBA referees have called 61 shooting fouls on 3-point shot attempts, compared to only 33 through the first 68 games of last year’s playoffs. This is an 85% increase!

From the 61 fouls called on 3-point attempts during this season’s playoffs, 21 were “4-point play” opportunities, meaning the officials called a shooting foul and the 3-point field goal attempt was made.  Fifteen of these 21 were converted into 4-point plays, while the ensuing free throw was missed on the other six.

In contrast, during the first 68 games of last season’s playoffs, only 6 of the 33 shooting fouls called on 3-point shot attempts resulted in 4-point play opportunities.  Five of the 6 were converted after the ensuing free throw was made.

This increase from 6 four-point play opportunities in last year’s playoffs after 68 games compared to 21 after 68 games in this season’s playoffs is obviously significant: a 250% increase).

Here’s a breakdown of the players who have been fouled on 3-point attempts this season, followed by a chart from last season’s playoffs after the same number of games played (68):

Players fouled on 3-point shots in 2014 NBA playoffs through 5-13-14

Players fouled on 3-point shots in 2013 NBA playoffs through 5-13-14

Although you would think it may be alarming to see such a large increase from one season’s playoffs to the next, we don’t think it’s a bad thing.  In fact, we think officials haven’t been calling enough fouls on jump shots based on our research over the past three seasons.

Thankfully, this season the NBA came out with new detailed guidelines on what constituted a shooting foul when contact was made on a shooter’s arm or hand, and to their credit, the officials have been enforcing them much more consistently.

There may be a reason why the league came out with these more specific guidelines this season instead of previous seasons.  Since we’ve reviewed video of every shooting foul over the past three seasons, we noticed there were huge discrepancies among referees in the type of contact they allowed on shooters’ hands, arms, and wrists, especially on long jumpers like 3-point shot attempts.  We scoured the rulebook for guidelines on the type of contact that was allowed on a jump shooter’s hand or arm, but there really wasn’t anything specific.

As a result, it seemed to be very subjective and was left up to the referees to decide on their own, which obviously wasn’t good since rulings were all over the map.  Even when you listened to television announcers analyzing this contact on video replays, some would say the contact was a foul while other announcers seeing the same type of contact would say it was legal.  What a mess.

After noticing these discrepancies in how referees called these kinds of shooting fouls, but with the lack of guidelines, last season we sent emails to the NBA league office asking for clarification through a new fan feedback email address they made public (here’s a link to our email text, if you’re interested).

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NBA league statements on missed calls could create unintended consequences

This season the NBA league office has released several statements acknowledging plays where they believe the officials made mistakes late in games that could have had an impact on their outcomes.

That includes one statement on Wednesday where they called out the officials (not by name) who missed a very difficult goaltending call in Tuesday’s Golden State-Dallas game that had huge implications for both teams fighting it out for playoff spots. Below is a screenshot of the statement posted on NBA.com.

NBA_statement_on_GSW-DAL-goaltend

These efforts by the league have been applauded by many (including myself) that publicly acknowledging these mistakes is good in high stake games like these, all under the guise of further transparency, along with a few other efforts like recently releasing internal memos the league office has sent to NBA teams this season.

I appreciate what the league is trying to do when the officials get a call wrong, but these statements tend to just say, “The refs were wrong,” rather than discuss how some of these problems might be addressed in the future.

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What we do

Our venture has logged just about every NBA referee’s call in a database since the 2011-12 season, and our data and analytics have been used by NBA teams to gain an edge since referees often can impact the outcome of games.

However, we do understand many NBA fans would be interested to learn about the tendencies of referees as well, especially when their favorite team loses a game because of a controversial call (or no-call) from a referee.

To get our updates, follow us on Twitter (@RefAnalytics) where we’ll occasionally release a few tidbits (quantitative and qualitative), usually after controversial referee calls, that might provide some context to NBA fans on why a referee made (or didn’t make) a particular call. Although it can’t change the outcome of a game that your favorite team has lost because of a call or no-call, perhaps it will shed light if that referee has a tendency to call too many (or too few) violations.

We do not plan to release a large amount of information about NBA referees through our Twitter account or this site. We believe this data should be handled responsibly because referees are human and have tendencies like everyone does in their jobs and businesses. That said, if you are in the sports media business and would like to incorporate NBA referee tendencies in your coverage in a responsible way, or you are with an NBA team that is looking to get deep insights on individual referee tendencies, feel free to contact us.


If you want to learn more about our research on NBA referee tendencies, make sure to check out our research paper we submitted to the 2014 MIT Sloan Sports Analytics Conference that was selected as one of the top sixteen research papers of the conference from over 300 submissions.

We also were interviewed by USA Today in a story that was published March 7, 2014…

Shown below are selected tweets that tell a little about our background, and may provide insights on our philosophy when it comes to the topic of NBA referee analytics:

Here’s what other folks have Tweeted that we’ve found interesting and relevant: