How well do Vegas futures predict playoff results in each sport?

Spurs_Tim_Duncan_Heat_LeBron_James_2013

Spurs and Heat… again.

On Friday, I wrote a post for FiveThirtyEight discussing the rampant inequality and predictability found in the NBA. I have a few more thoughts on that subject…

While the NBA has successfully suckered tens of millions of fans into believing the 2014 playoffs have been thrilling and unpredictable, with the LA Times even declaring, “March Madness suddenly seems like such a bore by comparison” (this is a pretty odd comparison considering the Final Four concluded with a No. 7 seed beating a No. 8 for the title), I’ve had a much different opinion, and this year’s predictable results simply fall in line with recent history.

While my original post mostly analyzed the odds distribution in each sport, I didn’t much consider the actual results, and it got me wondering… How well do those futures odds predict what actually happens on the court, as well as in other sports?

To analyze this, I ranked all the teams in each sport according to their preseason championship odds* (i.e. for 2014, Miami is No. 1, Bulls No. 2, etc.) I then plotted this rank against their eventual playoff results (0 = missed playoffs, 1 = lost in first round, 2 = made conference semifinals, 3 = made conference finals, 4 = made finals, 5 = won title) over the last four seasons. For comparison, I also included the NHL, a league that also has an 82-game regular season and four rounds of best-of-seven playoffs:

*Because any betting odds will add up to greater than 100 percent, I simply divided all the futures by the sum of all the teams’ odds to scale them down to 100 percent.

nba presason vs results

nhl presason vs results

The NBA has a clear strong correlation between preseason championship probability rank and playoff results, while the NHL is much weaker. Over the last four years, no NBA team ranked lower than fifth in preseason championship odds has made the finals. Compare that to the NHL, which has had six of eight non-top five finals teams in that time.

Here are the NFL and MLB distributions too:

NFL preseason vs results

(0 = missed playoffs, 1 = lost in wild card round, 2 = lost in divisional round, 3 = lost in conference championship game, 4 = lost Super Bowl, 5 = won Super Bowl)

MLB preseason vs results

(0 = missed playoffs, 1 = lost in Wild Card game, 2 = lost in LDS, 3 = lost in LCS, 4 = lost World Series, 5 = won World Series)

It’s easy to see how these other leagues’ plots differ from the NBA’s. Here are the correlations for each graph:

NBA = .647

NHL = .523

NFL = .440

MLB = .371

Clearly, the preseason favorites go further in the playoffs with a much higher frequency in the NBA than in any other sport.

Dominance of Miami

Much of the predictability in the NBA is due to the havoc the Miami Heat have waged on the wagering markets. To put Miami’s sports book dominance during the LeBron-Wade-Bosh era in perspective, here’s a scatter plot of the all the seasons in the MLB, NHL, NBA, and NFL over the last four seasons, plotting each team’s championship odds at the start of the season against their odds at the start of the playoffs.

AllOdds2

(Sorry, no pretty graphic with this one—just a screenshot of an R plot. Chartbuilder doesn’t take to kindly to doing scatter plots with multiple series.)

Only once in the last four years have the Heat not been favorites to win the title—the start of the 2011 playoffs, following the Big Three’s underwhelming debut regular season. Now, to really see how Miami’s recent run stands out, here are those odds when the four years for each team are averaged together.

AllCombo2

Over the last four seasons, the Heat have averaged 24.6 percent and 28.4 percent chances of winning the title at the start of the regular season and postseason respectively. Compare that to the Sacramento Kings, which have averaged 0.3 percent and 0.0 percent respectively over that time.

Another interesting takeaway from this chart is that the Patriots have often wildly outperformed preseason expectations during the regular season, accruing more than double the title odds by the time the playoffs start. The Lakers, on the other hand, wildly underperform (or are simply very overvalued at the start of the year), nearly slicing their preseason title odds in half over the course of the regular season.

Odds Distributions

Probably the most striking image from my FiveThirtyEight story was this line chart of the distribution of championship odds at the start of the season in each sport.

Pre line chart

When you zoom in on the bottom two thirds of the chart, you can really see the near-zero odds of the barren bottom 50 percent in the NBA.

Pre line zoom

This NBA inequality is still apparent come playoff time. (I separated the MLB data into the years in which there was only one wild card per league and years in which there were two.)

Play line chart

While the NBA may look like it’s made up some ground here equality-wise, it’s important to note that the NFL and MLB have byes and play-in games, a structural advantage that automatically adds greater disparity in championship odds. The average top NBA playoff team, which has to win four rounds for the championship, still has better title odds than the average top MLB and NFL teams, which only have to win three rounds.

Solutions

The day after my FiveThirtyEight story ran, the NY Times published a story that touched on very similar topics. Most interestingly came a quote from former Stanford professor Roger Noll, discussing one of my most despised regulations in sports:

“If you didn’t have an individual cap,” Noll said in a telephone interview, “if LeBron James was in a position to sell himself to the highest bidder, his salary would be much higher and you wouldn’t have a small number of top teams with more than half the superstars in the league.”

“It’s a big mistake, and the N.B.A. hasn’t adjusted. So if you have as many as 25 teams that know before the first game is played that they probably won’t even be in the conference finals, doesn’t that make the regular season seem almost meaningless, more of an exhibition than a pathway to a consequential championship?”

I couldn’t agree more (and plan to write more on this in the NBA off-season).

In previous posts, I’ve argued against the randomness and extreme parity of college basketball, much of which is due to the 68-team single elimination playoff format—a huge contrast to the NBA’s best-of-seven series. If that sounds like the complete opposite of my above criticism of the NBA, then you’re right. The NCAA lies too far toward the extreme randomness/parity end of the spectrum, while the NBA goes too far to the extreme predictability/inequality end.

You don’t want seasons to feel like they’re extremely predictable like the NBA, but at the same time, you want the true best team to win with a relatively high frequency so that it feels like teams are justly rewarded. It’s critical to have a good balance between the two, and finding that equilibrium is something sports leagues have wrestled with—and will continue to wrestle with—for decades.

 

Why prevent NBA teams from only playing four players?

BfwUmzMIgAETKbN

Chris Kaman seeing his psychiatrist.

Realistic rating: 9.5

Last night, Lakers center Robert Sacre invoked a little-known NBA rule when he fouled out of the Lakers-Cavs game. With the Lakers not having any players available on their bench at the time of Sacre’s sixth foul, they would have been down to only four players had Sacre been forced to leave the game, thus triggering Rule No. 3, Section I, which states:

“No team may be reduced to less than five players. If a player in the game receives his sixth personal foul and all substitutes have already been disqualified, said player shall remain in the game and shall be charged with a personal and team foul. A technical foul also shall be assessed against his team. All subsequent personal fouls, including offensive fouls, shall be treated similarly. All players who have six or more personal fouls and remain in the game shall be treated similarly.”

First off, let me say that as a huge proponent of instituting “power play”-type situations in many sports other than hockey (I’ll save that for a later post), I’m vehemently against this rule. Wacky things in sports like a shortstop having to pitch, a goalie having to take a shootout shot, or a quarterback having to punt are ALWAYS insanely entertaining—highlights fans talk about for years. Playing a basketball game with four players more than qualifies for that category. Why go out of your way to prevent such fun from occurring?

Possible exploitations

The other issue I have is that I don’t understand how referees can arbitrate when a team qualifies for this rule. The reason the Lakers triggered it was because they only dressed eight players that night, and that number shrank down to five due to a Nick Young knee injury, a Chris Kaman foul out, and a Jordan Farmar leg cramp all occurring prior to Sacre’s sixth foul. But how could the refs know if Farmar’s cramp was really a “cramp”?*

The reason I bring this up is because teams could theoretically lie about the health of their players if it would keep a star player with six fouls in the game. A prominent example of a situation in which a team could benefit from exploiting this rule would be Game 4 of the 2012 Eastern Conference Finals between the Miami Heat and Boston Celtics. When LeBron James fouled out with 1:51 left in the first overtime, the Heat fell apart without the league MVP, eventually losing in a second overtime to notch the series at 2-2. Since LeBron was such a valuable asset to have on the floor, it’s almost certainly  worth the tradeoff of having any potential fouls he commits be technicals, so the Heat would surely prefer to have him on the court, even with that corollary in place.

The issue, though, is that according to the wording of the rule, it seems that since the Heat had available players on their bench, LeBron could not remain on the floor. This is wherein my question lies: What would have prevented Heat bench players like Norris Cole and Mike Miller from suddenly “””””“cramping up”””””” (add like seven more quotation marks) and reducing the number of available Heat players to just five, thus forcing LeBron to stay in the game? (Even if the Heat couldn’t sub out for the rest of the game, retaining a player of LeBron’s caliber would still likely make such a ploy more than worthwhile.)

*It should also be noted that the Lakers were on the verge of putting Steve Nash—who was resting that night—in the game, but decided against it. Wouldn’t that technically have made him “available,” thus negating the Sacre situation?

Miscellaneous issues

1. Another issue about this rule is that it—admittedly, very marginally—changes the strategy of the game before a player fouls out. Whenever a player has five fouls, it gives a strategic edge to his opponents, because the player theoretically doesn’t want to foul out, so he may be a bit more tentative on defense, allowing teams to deliberately go at him when they have the ball. Without that fear, a five-foul player may continue to play at his normal defensive standard.

2. If the six-foul player accrues a tech every time he fouls, what happens if he draws two of these? Does he simply not have a technical foul limit anymore?

3. Can other players who had previously fouled out now come back in the game with the technical corollary in effect? So many questions.

4. What if Sacre suffered a truly debilitating injury. Would his writhing body have to lay in the corner of the court while his teammates played? Or would the Lakers have had to forfeit, even though they had a double-digit lead?

It’s worth noting that the Golden State Warriors encountered a similar situation in 2010, but when Devean George fouled out, the referees forced Don Nelson to play a clearly hobbled Chris Hunter.** This seems like a clear double standard compared to the one the referees employed for the Lakers last night.

**Nellie had to swap in three injured players, instructing each of them to throw a quick intentional foul, so that he could eventually put George back in the game. Here’s a video of some of that genius strategy:

Solution

Well, the obvious solution to me, as referenced above, is to simply remove this rule and force teams to play with four players.

If the league *must* have some form of this rule, then I’d simply suggest a steeper penalty than just a technical foul whenever the six-foul player draws a whistle to prevent any of the aforementioned chicanery. Perhaps something like a flagrant foul—where the team gets two free throws and the ball—would do the trick.

Bottom line: Teams playing four players would almost never come into play, so changing this rule really isn’t that intrusive. (According to SportsCenter, it’s only happened twice in the last 10 years.) If a team screws up this badly, let the opposing team (and fans) reap the benefits.