Is Baseball the Least Random Sport?
Former front-office analyst and now stats professor at Smith College Ben Baumer has a paper out, with cowriters Michael J. Lopez of Skidmore College and Gregory J. Matthews of Loyola University Chicago, that hopes to answer a question we’ve all thought about when our favorite team loses: how often does the best team win in a given sport? How much of our pain can we explain away with luck? The answers contain multitudes.
Their paper, which clearly attacks the main problems in answering the question, can be difficult for a layman to understand. But the basic genius in their approach may be using the betting line to judge team strength. That number allows them to compare different sports with different scoring systems and different amounts of team games.
After testing the line and finding it was a good estimate of team strength separately in each league, the analysts had to figure out the home-field advantage in each sport, the parity between teams, and then the estimated season-to-season and week-to-week variability.
Guess what: baseball had the smallest home-field advantage, with every baseball park scoring below every other sports’ locations other than the Rockies, who have a bigger home-field advantage than four hockey teams. Baseball also had the most parity and the smallest variability week to week and season to season.
So you might have guessed their conclusion — baseball is, indeed, the sport with the most amount of luck involved. The teams are packed in the closest, they have the smallest advantages from their parks, and the so the games are closest to coin flips among the sports. (Note: per Baumer et al., CDF denotes “cumulative distribution function… of 1000 simulated game-level probabilities in each league.”)
This, of course, has ramifications for running a team, ramifications we’ve probably seen recently. The combination of the added Wild Cards and all this parity has led to teams diving for the middle. The Cubs and Dodgers aside, most teams seem content to build a team with a true-talent win total in the mid-80s and hope the balls bounce their way in a given year.
You’ve seen evidence here of these sorts of things. When Dave Cameron wrote that losing on purpose was a bad idea because team projections can easily be off by 10 or more wins, when Billy Beane says “sometimes good things happen,” when the Braves sign Sean Rodriguez — that’s when you know that baseball itself knows how closely packed in the teams are.
But what does this mean for us as fans? That’s less clear, because luck means different things in different situations. When it comes to losses, luck absolves our team of guilt. And though parity and loss absolution are probably good things for the average fan — your team has the chance to win in any given game, and if it loses, you don’t have to feel so bad — it does break down on the extremes.
If every game was truly a coin toss, we wouldn’t want to watch, would we? There would be no meaning. We’d be watching the plinko chips bounce their way down to some random destination. Front offices would have no reason to build good teams, talent would be randomly distributed and randomly expressed, I’d guess. We’d be watching blips on a screen.
The absurdity of that language probably gives us a clue that we aren’t anywhere near that point in baseball. The Cubs had a great team and they won a bunch of games. They still lost 60-plus games, and that’s great. That’s a testament to the game’s parity — best in sports, apparently.
With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

I always felt like the NBA was the least random. I mean, each year you can probably pick from 4-5 teams who the champ is going to be, with a strong probability attached to just 2 or 3 (Warriors, Cavs). In the NBA, you can make the playoffs and still have virtually no hope of winning a title; not true in baseball
That’s why baseball is great
Agreed the NBA is least random, but there are benefits to that as well as drawbacks. The NBA Finals and/or Conference Finals are nearly always a showdown between the best teams in the league. We almost never get to see the best two teams in baseball face off in the World Series anymore.
Having 87-88 win teams win the World Series is not great. It’s crappy actually. The NBA has the best of both worlds; a long playoff season and still get the best teams in the NBA Finals. Since the NBA went to the 16 team playoff format in 1984 only one team seeded lower than #3 has won the NBA Finals. The 1994-95 Houston Rockets were the #6 seed but they were the defending NBA champions.
Yep. Just to piggy-back on what you’re saying – since 1984, those 94-95 Rockets were the only NBA team to win fewer than 54 games and won the title. THey only won 47 but had an inner-circle HOFer (Olajuwon) and traded mid-season for another HOFer (Drexler) and as you noted, were the defending champs. But it gets even better than that re: the NBA. I haven’t checked it in a few years, but as of a few years ago no team since 1984 had started a season worse than 6-4 in their 1st 10 games and won the title.
The NBA really needs to either shorten the season a bunch (I’ve seen suggestions of home-and-home with every other team – 58 games) or go to 8 team playoffs. Neither of which will ever, ever happen of course, so this post is pointless but still – the NBA season is wayyy too long. Then the playoffs are also wayyyy too long.
Season length vs. single-game reliability:
http://pages.ucsd.edu/~nchristenfeld/Publications_files/Sports.pdf
These professors are frauds; NFL definitely has the most parity.
“Holy cow, ease up there hot shot. That’s a pretty bold statement. I wonder what kind of data is at that lin–oh. Nice. *thumbs up*”
For anyone confused like I was, it goes by the year at the start of the season, not the year the superbowl was played.
Where the hell is Drew Brees!? This image just kicked my soul in the testicles.
“Where the hell is Drew Brees!?”
In the NFC.
A slightly higher rate of predetermination over a much shorter season does in fact create a greater sense of parity.
LOL! I didn’t know that the Belichick/Brady combo worked for multiple teams. My bad!
Hey, Dan Snyder is dying to know: why isn’t RGIII or Cousins in that lineup of faces?
There’s a few faces. Like the guy in white with the big forehead and the guy in orange with the even bigger forehead.
Of those 4 quarterbacks: Manning has retired. Brady is damn close to retiring. Roethlisberger has considered retiring.
I guess the NFL will have more parity soon. But at the same time, you replace good football with parity, and all of a sudden, parity doesn’t matter.
I know Vegas odds aren’t always scientific but the spread in ball games is always much much much lower than in any other sport.
Even when the #1 team played the #30 last year I don’t think you’d ever see more than 60% win probability for the better team.
It varies a lot with the pitchers of course but that’s not even close to being true. Conservatively speaking if the best team were a true 95 win team and the worst a true 70 win team, the best team is a 2-1 fave on neutral territory.
The heaviest favourite I saw last year was -370 (79%) for the Dodgers to beat the Reds in a game pitched by Kershaw. Over 75% is quite rare, even over 66% doesn’t happen more than a few times a week. But the Vegas line measures public opinon more so than team quality (they aren’t too far apart most of the time). I haven’t bet basketball in years but lines in excess of -1000 (91%) are possible, even -10000 (99%) for some college games.
This randomness is on a per game basis, however this is also interesting to think about on a season basis. Baseball accounts for its randomness in single games by having an absurdly long season. Football is much more predictable on a per game basis, but because the season is so short, might there be greater sampling variation for the season?
I think the NFL standings reward a blowout for a small portion of a game far more than MLB does.
If you equate the 2 seasons, there are essentially 10 MLB games’ worth of standings in 1 NFL game. If a MLB team wins 2 straight blowouts and loses the next 8 games by 1 run they’re 2-8. But a NFL team can blow an opponent off the field for an entire quarter and play 3 mediocre quarters around it, and be rewarded with essentially a 10-0 performance.
If home teams are more likely to blow an opponent off the field for a short portion of the game there is a great value to having this capability when the standings become final.
Which really clues you in to how truly desperate NBA basketball is for the common fan. Each game is highly predetermined, the season is 82 games long, and every round of the playoffs is a best of seven. Yuck.
Home Field Advantage might actually be smaller in baseball across the entire board. Accounting for a Coors Hangover could drop the Rockies below those 4 NHL teams.
I’m confused here. The headline asks, “Is Baseball the LEAST Random Sport?” But the study’s conclusion says it has “the MOST amount of luck involved.”
Had to keep the law of headlines in tact. So the answer is NO!
The absurdity of that language probably doesn’t give us a clue what this article is about.
It’s kinda funny that baseball had the smallest home field advantage when it’s the only one of these 4 sports that does NOT have a standard sized playing surface.
Baseball also lets the home team bat last (which is usually and advantage). And even in baseball, estimates seem to be that most of that advantage for the home team is in differential calling of balls and strikes by the Ump! (So it’s possibly official bias, not field differences or batting last.)
Basketball and Hockey by comparison have almost nothing but referee bias to explain their differences, and the noise effect at football games is probably a fairly small part of their difference.
Actually, teams in the NHL do get a few advantages on home ice.
Faceoffs – the home team gets “last stick” advantage for center ice faceoffs. It’s a small advantage, but still an advantage.
Last roster submission – again a small advantage, but the home team can make last minute adjustments based on the visiting lineup.
Last change – one of the bigger advantages in pro sports, IMO. During stoppages, the visiting coach must send his team out for the faceoff first. This allows the home coach to match lineups more effectively.
Yep. Good point.
Batting last has no advantage. That’s not where HFA comes from in baseball.
There is an advantage of playing at home that deals with rest as well. If a team is on a road trip and gets into the Hotel at 5AM the morning of a game there is a big disadvantage.
No there isn’t. In baseball.
I’m sincerely intrigued by this. Baseball *should* have the largest home field advantage due to this reason. Why do people think it doesn’t? Is a psychological factor on players from crowd effects? Is it worse officiating/officials influenced by the home crowd? Have studies been done on this? I find this very interesting.
Can’t they just look at the variance of betting lines in all sports? Largest variance means least luck and smallest means most luck. Would be a 3 or 4 sentence paper.
Hi MGL,
Nice idea, and one we talked about. Incidentally, I tried a similar thing here:
https://fivethirtyeight.com/features/on-any-given-sunday-nfl-favorites-win-and-underdogs-lose/
However, a weakness of that approach is that it’s tied to league schedules – for the NFL, which punishes top teams with more difficult opponents, this seemed particularly troublesome. Additionally, for this paper, we were interested in learning more about league’s than luck alone.
Surely you can “extrapolate” (maybe bad word) the lines to adjust for imbalanced schedules. I don’t think it will make any difference anyway. The SD of lines in baseball are going to be much larger than in any other sport. Imbalanced and biased schedules won’t change that. Don’t really need much of an analysis to figure that out.
In any case the only thing that determines the amount of “luck” is the spread of talent in the league. Once we know that we know everything. We can create the distribution of “Vegas lines” just knowing the spread of talent in the league. We just use odds ratio for each game.
That is one extremely confusing graphic.
I would like to see the statistics for whether baseball’s much longer season makes up for the randomness in terms of teams reaching the playoffs. also, is a 7-game baseball series more random than 1 NFL game?
Clickbait title that everyone knows is false.
Funny, I thought the only way to get league parity was to have a salary cap…
An interesting graph for sure, but it basically just tells people what they know already based off of experience.
Baseball is more random because individual players have less of an impact on the outcome of a year than in other team sports. In particular you can point to the NBA, which is basically unheard of to be a winner in if you do not have a superstar. Even the Spurs, whom some have said break that mold, had a sure fire hall of famer in Tim Duncan.
The NFL has a positional component to it with the QB. Success of a team long term is directly tied to having a QB. It’s the one position where winning becomes extremely hard without a good one, and winning a lot over a long period of time is impossible without one. when people point to how the NFL doesnt have parity, they neglect that the NFL has done everything in it’s power to ensure it happens by protecting and giving almost every advantage possible to great QBs.
Baseball has superstars, but look at the Angels last year. They didnt sniff the playoffs with the best player on the planet. That doesnt happen in the NBA. If Trout was a QB, his team would almost always make the playoffs at minimum, and if the GM was even decent he’d have a ring.