Supporting the Bucks with Support Theory

The Bucks are in a good position for the playoffs. They hold the best record in the league, guaranteeing home-court advantage. They achieved that record on the back of strong play, especially as the season progressed. Perhaps most importantly, they have prioritized health and thus enter the postseason (mostly) intact.

As Bucks fans - and especially readers of this blog - this isn’t news. We follow the Bucks closely and know that we have an excellent chance to win the championship.

But the problem is that we are biased.

I do not mean biased in the traditional, partisan sense: that we think the Bucks will win the championship because we want the Bucks to win the championship. Instead, I mean biased in the sense based on something called support theory.

Support theory was originally formulated by Amos Tversky and Derek Koehler. Here’s a quick description from some of my research:

Support theory is a formal model that describes how people estimate probabilities for events. The premise is that people make judgments based on descriptions of events, rather than the events themselves. For example, when asked to evaluate the probability that either (a) 1,000 people will die in a natural disaster, or (b) that 1,000 people will die in an earthquake, tornado, or other natural disaster, people assign a higher probability to the second category. The specific examples of earthquakes and tornados – “unpacking” the larger category of natural disasters into specific events – makes those instances salient...

Here, the event is a natural disaster. It is either described as simply a natural disaster or it is unpacked into earthquakes, tornados, and other natural disasters. Even though the underlying event is identical - earthquakes and tornadoes are just members of the category of natural disaster - people think that the second description is more likely. We know that earthquakes and tornadoes are natural disasters, but we might to forget to think of them (or hurricanes, or wildfires, etc.) when evaluating the likelihood of natural disasters writ large.

The fancy term for this aspect of support theory is implicit subadditivity. When we consider the category implicitly (i.e., without unpacking it), our evaluation of its likelihood is sub-additive (i.e., less than the sum of its members). If we were to add up the likelihood that we think that an earthquake will kill 1,000 people, that a tornado will kill 1,000 people, and so on, the sum of those probabilities will be higher than the likelihood that we think that a natural disaster will kill 1,000 people. In other words, we think that the whole is less than the sum of its parts.

In my study, we looked at support theory in the context of people rating the importance of territories in a fictitious country (which the participants would presumably not hold partisan biases toward). The ratings for each territory were lower when participants rated all of the territories rather than a single territory. In other words, when the other territories were unpacked, the single territory was viewed as less important.

Support theory, and our study in particular, have implications for us as Bucks fans. Our animating question going into the playoffs is: “What are the odds that the Bucks will win the championship?” This is akin to the single territory example above; the other teams / territories are not unpacked.

If we want a more realistic answer to this question, then, we would do well to ask this same question for every other team: “What are the odds that the [Celtics / Sixers / Cavs / Knicks / Nets / Heat / Hawks / Raptors / Bulls / Nuggets / Grizzlies / Kings / Suns / Clippers / Warriors / Lakers / Pelicans / Timberwolves / Thunder] will win the championship?”

Suddenly, the prospects of a Bucks triumph look a little less rosy - that’s a lot of teams! Some of those teams don’t have a chance in hell, of course (e.g., the Sixers). But some of them do, and even the ones that have a small chance add up.

If you follow the NBA at large, you are well positioned to engage in unpacking. In this case, you can draw on your knowledge of the Celtics and the Nuggets (and so on), offer reasonable assessments of their championship odds, and adjust the likelihood of a Bucks championship accordingly. Even if this knowledge doesn’t come as quickly to mind as Bucks knowledge, my study showed that simply having knowledge counters our bias.

But for this fan, at least - who is conspicuously absent whenever the staff does a roundtable on non-Bucks-centric content - I have to consciously remind myself of support theory. Beyond the generally positive outlook on the Bucks per se, it is important to consider other teams when supporting the Bucks.