NBA Star Treatment Bias and Our Own Cognitive Biases

Brent Asay/Utah Jazz

Benjamin Franklin once quipped, “In this world, nothing can be said to be certain, except death and taxes.” If dear old Ben were alive today he may have included a third certainly: death, taxes, and NBA fans complaining about star treatment by referees. Everybody thinks star players get preferential treatment, but do they?

There are plenty of anecdotal instances people could point to. For example, let’s think back to the two most memorable plays in Jazz history.

Firstly — and famously — we fondly remember John Stockton’s buzzer-beating-three to vault the Jazz into the 1997 NBA finals. After Rockets coach Rudy Tomjanovich watched Stockton lead a 13-point comeback by destroying Sedale Threatt, he switched Clyde Drexler onto Stock, hoping Drexler’s length would would disrupt the final shot. Enter Karl Malone, who arm-pinned, bear-hugged and Texas two-stepped Drexler from the top of the key to 5 feet above the break, leaving a lonely, helpless and hapless Charles Barkley to run at Stockton from afar. Malone was not called for the moving pick, and the rest is history.

Secondly — and infamously — Michael Jordan sank his own “The Shot” a little over a year later, pushing off against Jazz defender Bryon Russell to sink the jumper that won the 1998 NBA Finals. No call on the MJ clear-out, and the Bulls hoist another banner.

Those examples and a whole lot of conventional wisdom say that referees give NBA stars the benefit of the doubt, especially with Malone and MJ, reigning league MVPs in those respective seasons.

Evidence of a perceived star standard for calls exists in recent history, too. After a play last season where Derrick Favors appeared to get hacked on attempt but didn’t get the whistle, Jazz coach Quin Snyder stomped down the sideline, berating the official: “No respect! No respect!” Implied in this complaint is Quin’s belief that Favors is a star deserving of calls. Snyder might have still protested the no-call had it been a rookie or a scrub, second-class citizens who are expected to be the victim of bias, but he certainly wouldn’t have made his case based on “respect.” To Snyder, star treatment is axiomatic — it is a given. If basketball savant Quin Snyder takes disparate ref treatment as fact, it must be true, no?

Most players, coaches, GMs, fans and writers believe that the star bias of NBA referees is a given, just a part of NBA life. Now that the NBA provides a last two minute (L2M) report detailing call accuracy in close games, we can find out how true that assumption is.

From the NBA’s last two minute report

This data came from the NBA’s official last two minute reports from 2015 through 2017¹. The data was compiled by looking at only the personal fouls logged in the report², and “stars” are defined as players who made All-Star teams between 2013 and 2017³.

This data strongly refutes the “star treatment” hypothesis. With a standard deviation of ~2%, the likelihood of a call favoring a star is a coin flip — at least in the final two minutes of a close game.

Competing Hypotheses?

Are there competing hypotheses that allow for a star bias to exist? Is it possible that the last two minutes are an unrepresentative sample? In other words, do stars get better treatment in the first 46 minutes and not the last two? Do stars get calls in blowouts but not close games? These hypotheses are possible, but don’t seem likely.

Perhaps there are confounding variables in play that skew the analysis, a hidden factor that offsets the star bias? Perhaps, but none come to mind.

Or maybe the conspiracy theorists could posit that the back-office NBA officials are covering-up referee errors by not giving the objective truth about missed calls. Some hyper-specific L2M entries have been criticized, but in general it would be hard for the NBA to gloss something over to that degree. I have carefully reviewed hundreds of bad calls and the vast majority of corrections are obviously true.

Meta Bias: Biased about the Star Bias

So for now, let’s apply Occam’s Razor and assume these competing hypotheses are incorrect, and that the more elegant explanation is true: NBA referees do not have a star bias. We infer from this that there IS a bias in the NBA community, which believes that a non-existent bias is real. What cognitive biases might explain this mass delusion? Here are a few possibilities to consider.

We can break the biases into two buckets: origination and perpetuation

Origination is the trickier factor to evaluate: how did we first come to believe in the star bias? The genesis is as impossible to predict as the question of life’s origination on earth (pardon the hyperbole). Everyone has a natural bias to notice bad calls against their own team. Vivint SmartHome Arena does not rise in a standing ovation when the Jazz get a favorable call, fans just see it as the right call. But when a bad call goes against the Jazz, fans jeer and shout unrepeatable expletives. We have a negativity bias, meaning that unpleasant things have a greater effect on our psyche than positive things. This can be compounded by a victim mentality: we are more comfortable scapegoating an outside factor (officiating) than to blame the team we love. As when we get beat by a better team with more stars, we remember those calls against us and the perceived slight to our franchise.

Another possibility, one that I believe to be quite plausible, is that star treatment was real when the orthodoxy was born, and it now lives on only because of the biases that perpetuate it long after it has vanished. Remember, we have only 3 years of data, so a bias may have existed back in the MJ and Mailman days that doesn’t appear in this sample of L2M reports.

Anchoring Bias is when our brain relies heavily on the first information we perceive (the “anchor”) when forming our opinions. We are told there is a star bias during our NBA indoctrination and it sticks.

This can be compounded by Authority Bias as we attribute greater weight to the opinion of NBA experts. And further perpetuated by a Bandwagon Bias where a group adopts the same beliefs due to social pressures.

Further reinforcement may come from a Confirmation Bias, our tendency to seek information that verifies what we “know” to be true. So when we see a star receive a favorable call, we say, “See! stars getting calls!” Yet when a rotation player gets a favorable whistle or non-whistle, we dismiss it as routine and random.

The Boiling the Frog Bias suggests that our brains tend to not notice gradual changes, so if the NBA has corrected the problem incrementally over many years, we may have not noticed it. The admittedly disgusting metaphor is one of a frog in a heated pot not noticing gradual temperature change and remain submerged until death. Whereas a frog thrown into a boiling pot would immediately jump out. Whether this is real or apocryphal, please don’t report me to PETA.

Remember, our brains are constantly playing tricks on us and clouding our perception of reality. So the first time you see Ricky Rubio get hammered, followed by a no-call, consider that it could just be a random and honest mistake, and not because the guy who fouled him is named Steph Curry.

Let me know your thoughts and if you would like to analyze the data in different ways, your suggestions are welcome.