Home Court Redux

Kevin Drum notes two smart responses to the question of why home court advantage is so big, with one hypothesis pointing to the refs and another pointing to the idea that there are actually lots of differences from arena-to-arena.

The officiating issue is the most obvious one to point to, but it's always seemed to me that the scale of home court advantage is too big to be explained this way. If this were the dominant factor, I think I'd expect to see teams' point differentials be similar at home or on the road, but they'd have better records in the close games at home. But instead the effect seems big and systematic. And as Kevin says, what's weird here isn't just that home court advantage exists, but that it seems bigger than the advantage in football or baseball, even though in football the crowd can (and does) interfere with visiting team play calls and baseball stadiums differ dramatically from each other.

Comments

But we know NBA officiating is corrupt. Again, it was swept under the rug, but the NBA forbade its officials from gambling. So when Stern was forced to address it last year he found out basically all his officials were customers at casinos. Now instead of cracking down or stressing the rules, Stern just dropped the rule. So now NBA officials are free to gamble! The NBA makes NASCAR look impartial.

Posted by Rob | May 13, 2008 8:49 AM

I think the increase advantage in basketball is due to the travel schedule. In football, most teams don't arrive the night before the game but a day before that. In baseball, the away series is usually multiple games (a good test of this hypothesis would be to compare the records of the first game of an away series to the records in the rest of the series).

Basketball travel schedules are grueling. Often a team won't even arrive in the next city until 3-4am. They then play a game and repeat this many times.

Posted by Mike the Mad Biologist | May 13, 2008 8:57 AM

Doug Collins made a decent point in last night's Cavs-Celts games about the quality of bench play at home versus on the road. He argued that while a team's starters can and should perform nearly as well on the road as at home, most bench players tend to be youngsters or "energy" guys who feed off the crowd at home and tighten up on the road.

This has been true in the Celts-Cavs series, where Boston's bench dramatically outplayed the Cavs in Game 2, while the exact opposite happened in Games 3 and 4 in Cleveland. I don't think it's a coincidence that Rivers relied so heavily on PJ Brown last night in Cleveland, despite the availability of the more athletic and energetic Leon Powe. Powe has disappeared on the road throughout the playoffs (it doesn't help that the refs let him draw charges at home and call blocking fouls on the road). Meanwhile, PJ, while only a shadow of his former self, can be relied on to make short jumpers and not jump out of the gym on every head fake, despite the hostile crowd.

I'd like to see a breakdown of bench scoring at home versus on the road in the playoffs. I can't do it, since I work for a living, but maybe one of you semi-employed bloggers can put in the time. ;)

Posted by owenz | May 13, 2008 9:06 AM

Back in the day, Portland loosened their rims so that missed shots dropped close to the basket as opposed to tight rims which sent the ball out to the 3 pt line. This way Buck Williams knew exactly where to position himself for rebounds.

Posted by Ono | May 13, 2008 9:07 AM

You can't quantify it, but there is an advantage to having the home crowd provide some momentum.

But the big advantage is the refs, and I don't think the scale is too big to be explained that way. It's like that at every level. I watch a lot of Big 10 basketball, for example (Illinois fan), and the difference between a game in Champaign and a game in, say, Iowa City or Bloomington is at least six points right off the bat, just from the officiating, sometimes more. Remember that we're not just talking free throws, but starters in early foul trouble and everything that goes with that.

Look at the Lakers-Utah game. Rony Turiaf gets kicked out for a hard, but not out of the ordinary foul. In L.A., that might not even be a flagrant. In Salt Lake, it's an ejection. Part of it, I think, is a conscious decision by the refs that the home team will get the benefit of the doubt on close calls, but I think the refs are somewhat affected by the home crowd as well.

Posted by Seitz | May 13, 2008 9:08 AM

Most of the players in the NBA are very tall. At home, they have custom beds that are extra long. When on the road they sleep in standard hotel beds and their feet hang off. This lessens the quality of their sleep and effects their game.

P.S. baseball should have the largest home field advantage since the home team bats second. This is probably overcome statistically by differences in starting pitching.

Posted by Patrick | May 13, 2008 9:12 AM

There's a great home-court advantage in basketball because players have internalized the expectation that they play better at home, as well as the rationalization that they don't play as well on the road. This is especially meaningful in basketball because even the tiniest variation in effort expended will have huge consequences on the outcome of the game, plus the length of the basketball season gives those expectations and rationalizations a long time to sink in....you can't instantly go from "it's just one game of 82" to "every game counts" without a mental toughness that most players and teams lack to varying extents.

Posted by Rich | May 13, 2008 9:13 AM

think I'd expect to see teams' point differentials be similar at home or on the road

Why? I assume that different officiating means more foul shots for (one assumes) the home team, and less best-player court time for (one assumes) the visiting team. The point differentials should vary, I would think.

Posted by SomeCallMeTim | May 13, 2008 9:15 AM

As I said in the previous thread, refs in basketball simply affect the game more because they have more judgment calls to make, and could conceivably call a foul every possession. The differentials thing is ridiculously irrelevant, as calling the second foul on someone in the first quarter can be the most decisive thing that happens.

I'm from Boston College, which recently made a move from the Big East to the ACC. The idea that the refs favor the home team more in the ACC is an open secret, and it was stunning to watch in the first season. It has a massive impact on how the game is played. Everyone is more aggressive at home. They know they'll get the blocking foul called on the drive, or that they can swat at the ball without getting called. It drains the energy right out of the visitors, who have to be significantly better to overcome it.

An Simmons is right that the weaker the ref, the bigger the effect. If you watch a close game where you don't care about either team, you want the home team to win. It makes everybody happier.

Posted by nolaboyd | May 13, 2008 9:19 AM

Part of it, I think, is a conscious decision by the refs that the home team will get the benefit of the doubt on close calls, but I think the refs are somewhat affected by the home crowd as well.

And of course it is extremly well documented how different each NBA referee crew is in this respect. If Bennett Salvatore, Kenny Mauer and Dick Bevetta are reffing a game, you know the home team is going to get a ton of calls. Teams know this going in and adjust their aggressiveness accordingly. Meanwhile, if Joe Crawford and Steve Javy are reffing a game, you know the visiting team is going to benefit from a relatively even-handed effort from the refs.

The NBA has been accused of manipulating these rather obvious biases/differences between the refs to extend a given series or achieve a certain outcome. After all, there is no need for the NBA to hire "dirty" refs when it can exploit the glaring differences between its various referee crews through the non-merit-based assignment system it uses in the playoffs.

Posted by owenz | May 13, 2008 9:19 AM

Refs? I think only partly. I think it has much more to do with the psychology of the players. The short answer is "comfort." They are more comfortable at home, the place they play 40+ games a year, the place they live, the place where the fans go crazy just because they put the ball through the hoop.

In addition to talent, it is the mentally toughest teams that can block out the road disadvantages and win. Teams like the Spurs. We'll see if that pattern holds now that Tim Duncan is healthy or if age (decline of talent) is a bigger factor.

Posted by tremayne | May 13, 2008 9:22 AM

I think the familiarity aspect of an arena/stadium is important here. A pro football team doesn't play in it's own stadium enough (8 times a year) or frequently enough (once every two weeks) to gain as much of an advantage in their own confines. In baseball, a visitor's lack of familiarity is mitigated by the fact they stay in a foreign city for more than one game. In the NBA the home team plays 41 games in their own arena while the visitor never stays in one city more than a single game (or two or so during the playoffs). Add in the NBA's brutal travel schedule and a greater home court advantage starts to make sense

Posted by tom | May 13, 2008 9:30 AM

It would be interesting to do a controlled study with NBA players where they go out and shoot 100 3's at their "home" gym, then 100 3's at a random other gym, and see if there is a basic advantage to knowing, feeling comfortable with, a particular rim

Posted by Bill | May 13, 2008 9:31 AM

It used to be a bigger factor in college football. Bo Schebechler lost at home early in his first season at Michigan (1969), and didn't lose at home again until the last game of the season in 1975.

Posted by freddiemac | May 13, 2008 9:31 AM

Just checked the stats. I was very wrong about Joe Crawford. He is a total home crowd lover.

Just look at the numbers:

http://www.covers.com/pageLoader/pageLoader.aspx?page=/data/nba/statistics/2007-2008/referee_ats.html

In what other league could you have a refs giving home teams an advantage of anywhere from 8.40 to -0.67 points per game over an entire 82 game season? To put it in perspective, the Celtics had one of the greatest margin of victory averages in recent history this season, by outscoring their opponents by just over 10.0 points per game. In 68 games this year, home teams playing in games reffed by Tom Corbin outscored the away team by an average of 8.40 points per game:

http://www.covers.com/pageLoader/pageLoader.aspx?page=/data/nba/referees/2007-2008/referee403917.html

And it's not like Corbin was reffing a ton of high scoring laughers, either. The guy was 31-36 against the over/under, meaning he tended to ref low-scoring games.

Crazy.

Posted by owenz | May 13, 2008 9:34 AM

Matthew,

I think you are overstating the level of the advantage. During the regular season the home team wins about 60% of the time, so there is a swing in their favor, but in the playoffs, the teams are so closely matched that any swing can cause dramatic differences in winning percentages.

As for the reason for the effect, I'm sure it is all of the above working in concert.

Here are the regular season winning percentages for the home teams.
http://www.basketball-reference.com/

| year_id | Perc Home Team Wins |
+---------+---------------------+
| 1970 | 62.3% |
| 1971 | 60.2% |
| 1972 | 59.5% |
| 1973 | 62.0% |
| 1974 | 61.3% |
| 1975 | 65.0% |
| 1976 | 65.2% |
| 1977 | 68.5% |
| 1978 | 67.6% |
| 1979 | 66.5% |
| 1980 | 65.3% |
| 1981 | 62.1% |
| 1982 | 59.9% |
| 1983 | 62.0% |
| 1984 | 67.9% |
| 1985 | 63.7% |
| 1986 | 65.4% |
| 1987 | 66.5% |
| 1988 | 67.9% |
| 1989 | 67.7% |
| 1990 | 64.4% |
| 1991 | 65.9% |
| 1992 | 63.1% |
| 1993 | 61.1% |
| 1994 | 61.2% |
| 1995 | 59.7% |
| 1996 | 60.4% |
| 1997 | 57.5% |
| 1998 | 59.5% |
| 1999 | 62.3% |
| 2000 | 61.1% |
| 2001 | 59.8% |
| 2002 | 59.1% |
| 2003 | 62.8% |
| 2004 | 61.4% |
| 2005 | 60.5% |
| 2006 | 60.3% |
| 2007 | 59.1% |
| 2008 | 60.1% |

Posted by Sean Forman | May 13, 2008 9:39 AM

I believe the difference has more to do with the emotional state of the players than some people want to admit. I mean, those differences are obvious, and announcers talk about them all the time, but the kind of sports fan who devotes himself to arcane statistics like "defense-adjusted value against replacement" (naming no names) is likely to privilege the importance of measurable differences--like the number of fouls called--over the relatively fuzzy and hard-to-measure factors like incremental differences in player self-confidence and enthusiasm.

I know we've all agreed that these players are professional gladiators who, with their superior mind-over-matter mental toughness, can override the influence of such girly forces as emotion. But that don't make it true. Playing basketball well is a lot like playing a musical instrument at a high level. Ask Yo Yo Ma if his mood affects his performance.

Why is the effect bigger in basketball? I think it's because the crowd is closer than in football or baseball, and not separated from the action by a glass wall, as it is in hockey.

Posted by FearItself | May 13, 2008 9:42 AM

You're reporting on Kevin's reporting on comments that appeared in your own thread? That's hilarious, Matt.

Posted by phil | May 13, 2008 9:43 AM

This article

http://www.guardian.co.uk/sport/2008/feb/03/features.sportmonthly16

argues that home teams tend to have higher levels of testosterone (presumably some sort of evolutionary psychology thing) so play with more energy and agression....

Posted by Andy | May 13, 2008 9:43 AM

There's a study on home court advantage, discussed here (http://sabermetricresearch.blogspot.com/2008/05/back-to-back-nba-games-and-home-field.html#links), "The Role of Rest in the NBA Home-Court Advantage," by Oliver A. Entine and Dylan S. Small. Here's the abstract:

"To date, the factors which lead to the very large home court advantage characteristic of the NBA have not yet been well isolated. This study analyzes the relationship between that home court advantage and the comparatively fewer days of rest between games that the NBA schedule imposes on visiting teams. A statistical model has been developed and applied to the NBA data for the 2004-2005 and 2005-2006 seasons to estimate the importance of the effect of rest on the magnitude of the home court advantage. The results indicate that lack of rest for the road team, while not a dominant factor, is an important contributor to the home court advantage in the NBA."

Seems plausible to me.

Posted by Donald A. Coffin | May 13, 2008 9:45 AM

You don't read your own comment threads, do you? Because I thought your commenters offered several other good explanations in addition to those. It's a bit extra that Kevin Drum seems to have read your comment thread when you did not.

Of course, you're probably not going to read this either.

Posted by Antid Oto | May 13, 2008 9:46 AM

The effects (such as they are) of home court advantage are multiplied in the playoffs by the extreme emotions and extreme fatigue experienced by the players. It's not that home court is all that great of an advantage, it's that the margins by which such influences overlap and affect the games are so very very thin. We're talking about a lot of strung out ballers here.

As for the Celtics: Paul Pierce, Kevin Garnett and Kendrick Perkins also became first time fathers this season. (Scalabrine too, but he's not playing much now...) Don't underestimate the emotional roller-coaster they've been on this year... Speaking as a father myself, it's a HUGE letdown to leave your child for even a couple of days and HUGE shot in the arm to come home and see him/her. Pile on the emotions of playoffs... Lets see you try to play with consistency..

Posted by petr | May 13, 2008 9:47 AM

I think the impact of officiating could have an impact on players' decisions to the home court teams' advantage.

If LeBron James gets the call more often on the home than on the road when he drives to the basket, then he would drive to the basket more often than hoisting up a lower percentage jump shot. So the Cavs would not just benefit from the additional calls, but from choosing a higher percentage offensive play.

Tack on foul trouble, and James not getting called for offensive fouls and not getting into foul trouble, and the effect can be dramatic.

Posted by JohnMcG | May 13, 2008 9:56 AM

It's also a lot easier to fit players' extra-marital affairs into baseball and football road schedules than into the more grueling NBA schedules.

Posted by phil | May 13, 2008 10:08 AM

I believe the difference has more to do with the emotional state of the players than some people want to admit.

That's really all there is is to it. I don't see why the phenomenon is treated as such a mystery.

Because these guys are all supposed to be mythically polished professionals who are uber-disciplined "self-starters" or whatever, and are not supposed to be influenced by either a hostile or friendly environment, there is this ridiculous conspiracy of bullshit and denial among players, coaches and the media about admitting the obvious. But the fact is that most players seem to experience huge bursts of energy and confidence when 18,000 fanatics are screaming for them, and they are intimidated, diminished and depressed when 18,000 people are screaming against them. Yes it is most obvious with young "energy guys". But it is also true of older veterans.

I mean, this is totally obvious to any basketball fan with eyes. When the fans are rocking, the home town players have wings; they're flying. They have so much adrenaline-rushed energy that they are almost coming out of their shoes. The fans lift them up and carry them. The visiting players often look dazed, blank and somewhat frightened. It's even more of a factor in the playoffs, because the fans are on the whole much louder and more fanatical during the playoffs. They sustain their energy for longer periods of time, and at a higher amplitude.

Posted by Dan Kervick | May 13, 2008 10:25 AM

I have no doubt there is some difference in officiating, but I am in agreement with Matt that this cannot explain the entirety of the situation. The Celtics against a below .500 team should be easily overcoming differences in officiating.

Note also that really quantifying differences in officiating requires actually auditing a ton of games play-by-play and making objective judgment calls. You can't just look at the differences in numbers of fouls called, because which way fouls go already is dependent on how well you're playing! Not just in the sense that better play is maybe unfairly rewarded, but more importantly in the sense that if you're a step slower, if you're getting beat to a position, then you're going to commit more fouls. Fouls are often not the fouler doing something wrong per say, just his opponent moving a little faster and the fouler not being able to react in time.

Anyway, the theory about sight-lines behind the basket affecting shooting I think is worthwhile investigating. I'm not volunteering, but I would think that this could be pretty well answered one way or another by doing sufficient analysis on shooting percentages, particularly looking at players who have moved from one home arena to another. Does Derek Fischer shoots as well in Utah this year as he did last year, better than he does in other road arenas, and better than most players in road arenas? What about other players who have moved?

However, the one thing that makes me skeptical about the sight-lines is that baseball hitting should be expected to have a similar effect. And so it probably does not account for all of basketball's home advantage.

A sport that should be brought up for a comparison is soccer. Like basketball, soccer stands out as having an incredible home advantage. Top soccer teams will lose a few away games per year, but will go years between home losses.

Refs are a big factor in soccer too, with a couple of calls being able to completely change the result of a game, unlike basketball where realistically the referees can only push a close game one way or another. But then again, in some games referees in soccer can have little to no effect at all (because only calls that directly affect goals make a big difference, whereas all other calls make a minute difference relatively). So again, should be easy to analyze calls made in context, objectively judge their fairness, and determine if that explains the entirety of the home advantage.

If I had to guess, I would say that basketball and soccer home advantages do in fact come down to that messily impenetrable topic of psychology after all. Both games are in this context free-flowing games, where team effectiveness has a lot to do with things like players moving continuously and aggressively even when they are not part of the play at the moment. Players at some point or another all must give into human imperfections in focus, and be selectively lazy on some plays.

This slacking off is really easy since a lot of instances of hustle in basketball and soccer are situations where the hustle will not be rewarded. Most of your defensive rotations are to cover a guy who won't get the pass anyway, and most of the times you make the rotation in time the reward is just that he passes somewhere else or manages to shoot anyway. Boxing out rebounds is the same thing - most rebounds you will not get because half the shots go in the basket and don't rebound at all, and of the rest you only even have a chance to get the ones that come in your direction. In short, hustling in basketball is about doing twice as much work to get 5% more benefit. A benefit that is huge accumulated over the course of a game, but very minor when it comes to motivation through reward.

Soccer is very similar. Goals almost never happen. An extra step is almost always meaningless. But 1000 extra steps and one of them might be the one that scores or saves the crucial goal.

So my guess is that players in front of a rabid home crowd slack off less, just a little bit less, enough to pay big dividends when accumulated from most of the team over the course of a game or a season of games.

I think this fits the baseball/football test, because baseball and football are always brief spurts of action from a start position. Focus for each play matters, true. But maybe not as much, because there's less ambiguity about when there's a chance for you to hustle and when there isn't. If you're in the batter's box, or you're lined-up at scrimmage, you know that you have to focus and explode with 100% effort for that one moment. You know clearly whether or not you put in the effort on each pitch or play. In basketball/soccer, that moment that an active player could have taken an extra step, gone on a cut or a run, gotten a crucial steal leading to a fastbreak/counter attack -- that moment is not clear. The players don't know themselves when they missed them.

Unfortunately, I don't think this theory is as testable. Ideas? Regressing so called "hustle stats" in basketball at home and on the road, things like rebounds, loose balls, steals?

Posted by Will Hutchinson | May 13, 2008 10:27 AM

I think the increase advantage in basketball is due to the travel schedule.

This might explain the discrepancy during the regular season; the NBA regular season schedule is uniquely difficult for traveling teams. It is the one sport where you can play 3 games in 4 nights (which one may also do in baseball, but not in 3 different locales). But that advantage should totally evaporate during the playoffs: when teams play every other night, both teams are traveling on the same schedule. Yet it seems the home court advantage is just - if not more - pronounced during the playoffs.

~
baseball should have the largest home field advantage since the home team bats second.

This should only produce a slight advantage in that small percentage of games that are tied going into the final inning.

The one sport where the rules truly are tilted in favour of the home team is hockey: home team gets the last line change, which is a decided advantage when trying to match personnel. The home team also gets its bench nearest its own net for 2 of the 3 periods (making it easier to change shifts on the fly) and gets to put its stick down last in the faceoff circle. I would also say that there are more noticeable differences in the playing surface/area in hockey than in basketball.

~

A pro football team doesn't play in it's own stadium enough (8 times a year) or frequently enough

I don't think this does justice to how very different the football stadiums are from each other. Don't forget, teams are actually constructed based in part on the stadium they play in. You can have teams from a cold weather grass stadium going indoors to play a turf team in a dome. It is a much different experience to run on grass, vs turf, and even outdoor turf vs indoor turf are different (fastest indoors because the surface is level due to no drainage).

Posted by McKingford | May 13, 2008 10:28 AM

One thing you shouldn't fail to underestimate is the travel component. NFL teams only travel once a week, so there isn't as much of a burden to traveling whereas in other sports travelling is nearly constant, wearing on players as they sleep in strange beds, wake up in strange rooms and eat different food every day, messing up their routines (something that's insanely important to a lot of professional athletes).

So how come home field/ice isn't as big in MLB and the NHL? Well, in those two sports you have one particular position (starting pitcher, goalie) that shoulders a much heavier proportion of the outcome on their play than any other position. A starting pitcher that has 5 days off isn't as likely to be impacted by constant travel as an everyday player, and it could be the case that the best goalies (hence the most likely to start in the NHL) are the ones who are able to shrug off the rigors of constant travel (or that teams are more likely to give the starting goalie a game off on the road).

Posted by Tom | May 13, 2008 10:30 AM

The home team also gets its bench nearest its own net for 2 of the 3 periods (making it easier to change shifts on the fly)

Er, think about that one for a minute. If the home teams' bench is closes to the home team's net, then the visitors' bench, then the visitor's bench would be closer to...

Posted by JohnMcG | May 13, 2008 10:38 AM

And so it probably does not account for all of basketball's home advantage.

Has there been some indication of exactly how large this advantage is? I've been guessing that it's a few points (say three), which could be enough to turn a win into a loss, but isn't a huge number as against the number of points a team might score.

Posted by SomeCallMeTim | May 13, 2008 10:42 AM

Baseball stadiums have very different layouts, but batting average for balls in play is largely random anyway, so the difference isn't as big as you'd think. In any event, the home team in baseball has about a 55% chance of winning any game, so there's still a very non-negligible effect.

Posted by phil | May 13, 2008 10:42 AM

Anyway, the theory about sight-lines behind the basket affecting shooting I think is worthwhile investigating.

I play a lot of basketball. I'd say this is pretty much meaningless - you pick up the sight lines in about 2 minutes of shootaround; notice how the thousands of people doing crazy things behind the backboard has zero effect on free throw shooters?

The one component of basketball that I can see being different from place to place is the give in the rims (although this might be more standardized in the NBA). Nothing worse than playing with stiff rims - although I'm not sure this would necessarily advantage any given team.

~
I think it's because the crowd is closer than in football or baseball, and not separated from the action by a glass wall, as it is in hockey.

Have you been to a hockey game? I definitely think a packed hockey arena gives the biggest vibe of any pro sport (which is why hockey has never really taken off - so few fans actually see games in person). I think your theory might explain qualitative differences in officiating (where the fans are closer to the refs in bball) more so than player performance.

Posted by McKingford | May 13, 2008 10:44 AM

Like someone said above, a big factor on botht he teams and the refs is the closeness of the crowds. You have 15,000 yelling angrily at you not more than 20 feet away and your basically wearing underware? Have you ever got chewed out? Multiply the feeling of having one person yelling at you by 15,000. It has to effect your concentration.

Posted by cw | May 13, 2008 10:46 AM

Er, think about that one for a minute. If the home teams' bench is closes to the home team's net, then the visitors' bench, then the visitor's bench would be closer to...

D'Oh!

Posted by McKingford | May 13, 2008 10:50 AM

notice how the thousands of people doing crazy things behind the backboard has zero effect on free throw shooters

Quick release isn't a particularly valuable free throw shooting skill. I'd be astonished if sight lines don't matter.

Posted by SomeCallMeTim | May 13, 2008 11:00 AM

The post seems highly basketball centric. Home field/home region advantage is big factor in every sport.

Check out Brazil’s world cup record when Europe hosts compared to anywhere else hosting.

The basketball focus is getting myopic.

Posted by Christopher Colaninno | May 13, 2008 11:05 AM

FearItself, Doug Collins, and others are right.

In basketball the fans are on the court. It's hard to capture what's that like on TV, but for the players on the court who hear and feel the crowd at an intimate distance, it can have a tremendous effect on adrenaline and confidence levels.

A good home crowd gets into the head of the visiting players. One or two hecklers can make a visitor lose focus, especially the younger guys, in whom ego still reigns. They start playing self-consciously, start playing "with too much head". This starts a downward spiral of a kind of "proprioception", a physiological phenomena where "conscious perception on the part of the individual of effort by his individual muscles increases as an exponentially decelerating function of the actual force applied." Sometimes consciousness gets in the way, and this is precisely what a good home crowd does to a visitor.

So you have two simultaneous effects: the home team's adrenaline and confidence levels stay high and thereby keep the players "zoned in", and the visiting team is forced to constantly fight against the very human tendency to access conscious control when things aren't working out, a temptation that is magnified by the hostile crowd.

Posted by JA | May 13, 2008 11:10 AM

It's not the crowds or the refs. I might buy the bench energy argument for the first game of the season, but this is after 80+ games.

It's simply practice, as anyone who played college bball or beyond would know. I can outshoot larry or michael in my driveway cos I've logged thousands and thousands of shots there. It has to do with lighting,colors and depth perception (Remember, backboards are glass ). As Coach Wooden might say, it's the little things that count. It's sleeping in your own bed vs sleeping in a hotel. It's eating a homemade meal vs eating at a restaurant. etc.. etc..

Look at home court advantage for college teams and it actually becomes amazing how the NBA players have been able to close the gap.

Posted by Brian Holmes | May 13, 2008 11:47 AM

Because these guys are all supposed to be mythically polished professionals who are uber-disciplined "self-starters" or whatever, and are not supposed to be influenced by either a hostile or friendly environment, there is this ridiculous conspiracy of bullshit and denial among players, coaches and the media about admitting the obvious. But the fact is that most players seem to experience huge bursts of energy and confidence when 18,000 fanatics are screaming for them, and they are intimidated, diminished and depressed when 18,000 people are screaming against them. Yes it is most obvious with young "energy guys". But it is also true of older veterans.

This was really obvious in the Shaq-Kobe Laker era. Shaq is a home court player and Kobe is a road player. It's one of the most amazing things about Kobe that he can play so well on the road.

Posted by mpowell | May 13, 2008 11:55 AM

"[the home team batting second] should only produce a slight advantage in that small percentage of games that are tied going into the final inning."

This isn't strictly true. Remember the old saw about playing for the tie at home, the win on the road. A manager who follows this strategy will play differently when one run down in the ninth, depending on whether he is at home or on the road.

Posted by Richard Hershberger | May 13, 2008 11:56 AM

Remember the old saw about playing for the tie at home, the win on the road

Uh yeah, except that's in basketball, not baseball.

Posted by McKingford | May 13, 2008 12:33 PM

Remember the old saw about playing for the tie at home, the win on the road

Uh yeah, except that's in basketball, not baseball.

I'm pretty doubtful any MLB manager would play this way, but to the extent he did, it would *not* produce an advantage (which was my essential point).

Posted by McKingford | May 13, 2008 12:35 PM

Remember the old saw about playing for the tie at home, the win on the road

I hadn't heard this before, but it makes sense in basketball. If you're down by 2 with 10 seconds left and you have a 50% chance to make a 2 and a 30% chance to hit a 3, unless you're a decent favorite in overtime, it makes sense to go for the 3. And whether you're a favorite in overtime or not depends on whether or not you're at home. I've actually been kind of amazed that NBA teams will go for 3s in this situation b/c if it was the NFL, the 'no balls or brains here' rule would always dictate playing for the tie.

Posted by mpowell | May 13, 2008 12:51 PM

As to whether or not we're beginning the discussion with an overstatement of the home team advantage in basketball, I should think that the opposite may be true: we may be understating the home team advantage in baseball.

Wikipedia has some interesting links:
http://en.wikipedia.org/wiki/Home_advantage

Stating the home advantage for some sports as follows:
NBA - 3.2 pts
NCAA basketball - 4.2 pts
NFL - 1.44 pts
NCAA football - 1.94 pts
NHL - 0.31 goals
MLB - %8 difference in win percentage (using pythagorean theorum of baseball that works out to on the order of 0.5 runs)

Given the relative value of points in different sports, that almost makes basketball look like the _smallest_ home advantage, since 1.44 points in a football game that averages - what 40 combined points per game - has got to be worth more than 3.2 points in a basketball game where the combined points per game is around 200.

If the assumptions about home advantage not being as big in baseball and football are thrown out, then this becomes a really general question about road teams in sports.

I think there are two major theories that are surviving all of the criticisms provided: 1) the detrimental effects of travel, and 2) the psychological effects of the crowd.

Luckily travel is a fairly quantifiable thing. I have seen studies in showing, for instance, teams traveling West to East having worse road records that teams traveling East to West due to the different effects of jet lag whether you're gaining or losing hours. And there are loads of scheduling issues that are well discussed, such as a hugely detrimental effect on the team playing a second of a back-to-back in the NBA. There should be a broad way of surveying data on distance and timing between games in which, if travel effects were a big component of the home advantage, you'd expect to see those effects reduced in the case of shorter travel destinations and in the case of long rests between arrival and play times.

There should be ways to look at unique mixed crowd kinds of situations as well. College football, and club soccer both have relatively short travel distances and very mobile fan bases so you end up with a lot more away fans in the stadiums. Ditto for interleague play in baseball, where when the Yankees or Red Sox come to a NL Central or NL West team for their one trip every 3 or 6 years, their fans pack the place, along with the long history now being developed of frequent Subway/Freeway/Bay series (Yanks vs Mets, Dodgers vs Angels, Giants vs A's) throughout the season. How do the Lakers and Clippers stats track their averages when they play "away" games in their home building? I believe they also have the unique situation where because it's basketball and there's less room in the arena and so Clippers fans tend to dominate the crowd when it's officially their home game, and the Lakers fans dominate when it's theirs.

Unfortunately, bringing up "psychology" tends up give the argument a vagueness that makes it hard to pin down what you're saying, and harder to isolate the interdependent effects. If the performance of athletes has a measurable psychological dependence on their fans' support, then surely the performance of the fans might possibly be psychologically dependent on how good their athletes are, and so now you're trying to untangle the feedback between fans cheering their good teams and booing or not caring about their bad ones.

Logically, that's a difficult problem to pull apart. Of course, as a fan though that is all the more reason to give your all to support your team - just in case it really does make the difference!

Posted by Will Hutchinson | May 13, 2008 2:06 PM

I wonder if subtle differences might have a bigger effect than big ones. A right field fence that's 20 feet closer is hard to miss, but a bouncy spot on a blonde wood floor isn't something that's going to stick with you, even after the first few times you encounter it.

Posted by MikeT | May 13, 2008 2:17 PM

Because wives/girlfriends are at home, so players get to sleep earlier, while on the road, temptations are endless?

Posted by Steve Sailer | May 13, 2008 2:21 PM

1. Communication
2. Sight Lines

1. I'm astonished that no one has rejected the argument that crowd noise is more of a factor in football than in basketball. Don't those pointy ball guys have radios in their helmets now? Verbal communication in football is mostly letting everyone know changes to the starting play and moving with the snap count. Basketball is a MUCH more fluid game, with players changing their "routes" on the fly and doing it multiple times in a single possession. Some of the best coaches consider talking well to be THE most important factor in team defense, as requests for help, and players being routed to cover a person or a spot are almost always verbal. If your teammates can't hear you, that's easily worth 10 points against you in defensive breakdowns per game.

2. Sight lines -- this might be better termed "distance perspective". This is a non-factor in a lot of gyms, but the effect is massive if you've ever shot in a stadium designed for sports with bigger fields than a basketball court. Visual perspective is determined by comparing objects in the foreground with a background. If the roof and crowd are so far away from you that there really isn't a background to judge against, it's EASY to airball a baseline shot by misjudging how close or far the basket is from you.

Posted by DMoore | May 13, 2008 3:02 PM

In football, the home crowd is encouraged to make noise when the home team is on defense, and to be quiet when the home team is on offense (a practice I find somewhat distasteful -- I hate when I see Peyton Manning coming out of the huddle telling the crowd to settle down).

If things are as DMoore suggests, basketball crowds would be encouraged to make noise when their team is on offense, and to be quiet when their team is on defense. But this isn't what happens. If anything, the reverse happens, and they crank up the "DE-FENSE" chants when the other team has the ball. So, if crowd noise is a negative factor in team defense, there's no reason to believe it would effect the visiting team more than the home team.

----

I still say that it's not so much officiating bias so much as the perception of officiating bias, leading home players to do things like take the ball to the hoop and visiting players to back away from possible contact and launch lower percentage jump shots.

Posted by JohnMcG | May 13, 2008 3:51 PM

I think the NBA is a great league with ludicrous rules of play that change all the time..travelling is ok for the stars (Michael Jordan had 7 steps to get where he was going! lol..exaggeration but watch some of his layups..hilarious), and the superstars are basically immune from fouling out. Everything is just way more pronounced in the playoffs and the inconsistencies are more glaringly obvious.

I know a few ex-NHLers who can tell you exactly how a certain ref or linesman will call a game. You have to adjust to them and the worst ones are the guys who change in the 3rd period. Some are far more vulnerable to crowd reactions and will call to avoid controversy.Some are just power freaks. Some are wimps.

I think the Boston/Cleveland series is just an extreme example of how officiating changes the nature of the game and how it is played. They give the advantage and calls to the home team.

Posted by Rob D | May 15, 2008 5:44 PM