Archive for the 'Analysis' Category

In gathering links for StatHead yesterday, I came across this post at the Wages of Wins, wherein Prof. Berri mentions that the losses of Allen Iverson, Carmelo Anthony, & Rudy Gay did not hurt their respective teams. He then writes:

"In each of these examples, the loss of a scorer led people to forecast doom.  In each case, the team losing the scorer managed to survive and even improve.

Readers of The Wages of Wins and Stumbling on Wins understand this basic story. Scoring is overvalued by many NBA observers.   Top scorers do not always have the impact on wins that people imagine.  But no matter how often this story repeats, each time a scorer is lost we still see the same arguments offered by adherents to the conventional wisdom (for example, this week the Grizzlies insisted they would never dream of letting Gay depart)."

That's anecdotal evidence, though. What if we looked at every instance of a team losing its leading scorer? Would the typical team in that situation be impervious, or are those just a few cherry-picked exceptions to a larger rule?

Well, luckily, at BBR we have boxscores for every regular-season game since 1985-86. So I gathered our data, considering a team's "leading scorer" to be the player who led the team in PPG among players who played more than half of the team's games. I then looked at each team's offensive rating in every game, noting whether the designated "leading scorer" played in that game or not.

I also accounted for the strength of the opposing defense in each game by measuring how many pts/possession the opponent allowed in every game of the season except the one at hand. The end result will measure how well each offense performed relative to what we would expect from a league-average team facing the same opponent -- split by whether the team's "leading scorer" played or not.

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For the first time in three years, LeBron James did not give an acceptance speech at the Most Valuable Player's press conference. Now, as he faces his successor at the podium, Derrick Rose, in the Eastern Conference Finals, James is hoping his Heat can do exactly what the Magic and Celtics did to him -- prevent the reigning MVP from advancing to the NBA Finals.

In the NBA, the Most Valuable Player carrying his team to the brink of a title is the rule, not the exception. Since the league began handing out the hardware in 1956, the MVP's team has appeared in the championship round 28 times, good for a 51 percent rate. And during the NBA's halcyon era of Magic, Larry, and Michael, the clip was even higher: from 1983-2003, the MVP made a Finals appearance in 16 of 21 seasons, more than 75% of the time. In a world where current players are largely measured against those three names alone, it makes headlines when a reigning MVP fails to reach the league's grandest stage.

Perhaps this is why the drought of recent winners has been met with so much scorn. Since 2004, only one MVP (Kobe Bryant in 2008) has led his club to the Finals. The others -- Kevin Garnett, Steve Nash, Dirk Nowitzki, and James -- flamed out in the Conference Finals (or in the cases of the latter two, earlier), provoking backlash from the Skip Bayless set and anyone else preoccupied with legacies or comparisons to long-retired legends. That it has been viewed as a blemish on James' otherwise staggering resume is undeniable.

Yet now he has a chance to inflict the same criticism on Rose, the youngest MVP in league history. It's strangely fitting, because their paths have run parallel ever since the Rose-for-MVP talk rose from a whisper at the lunatic fringe of Bulls fandom to a din heard across the entire country. In the wake of 'The Decision', the media tried to talk itself into casting Kevin Durant as James' foil, but Rose out-Duranted everyone, ranging from his own sharp improvement to the Bulls' unexpected #1 seed and the endearingly humble manner in which he carried himself (culminating in a truly beautiful moment at his MVP presser). In the minds of many, he embodied the yin to James' preening yang.

For these reasons, the media will doubtless go easier on Rose than they did James, should the Bulls' season end early. And by the same token, the fact that James felt he needed two other big names, one of whom is nearly his equal in the universe of NBA megastars, to reach the Finals again will continue to dog him if the Heat prevail. But even if his legacy cannot be fully repaired through victory, it's clear that in a twist of fate, the only way James can gain some measure of redemption for his "incomplete" MVPs of 2009 and 2010 is to stamp Rose's 2011 award with the same stigma.

With the Magic, Lakers, and now Celtics being dispatched from the playoffs, I was thinking about whether a down period was necessary for teams that had been at the top for multiple seasons when their run was finally over.

Part of Danny Ainge's rationalization for the Kendrick Perkins-Jeff Green trade was to make the Celtics younger and give the team a solid player in the future. But do (older) mini-dynasties like Boston's ever really have a future? Does a modern NBA team ever successfully rebuild on the fly, or are good years always followed by a transition period of losing? Instead of making any attempt to build a future, should he have just committed to the 2011 team and accepted losing down the road?

Let's go to the data -- every team that went to at least 2 conference finals in 3 years, and their winning percentages in the next 5 years (Y+1, Y+2, ... , Y+5). "Age" is the team's minute-weighted average age in year Y's playoffs. "< .500" and "<.350" are the # of seasons in the next 5 that they posted a a record worse than .500 and .350, respectively. Enjoy: Read the rest of this entry »

Since we're in the thick of the playoffs, it seems appropriate to revisit this post from last June regarding the importance of each game in a best-of-7 series:

We can try to quantify [the relative importance of each game] by looking at the potential swings in each team's probability of winning the series based on the outcome of a given game. Let's establish a scenario where two morally .500 teams are playing each other in a 7-game series; the home team in any game has a 60% chance of winning (60% traditionally being the NBA's home-court advantage), and the away team has a 40% chance. At the beginning of a series in the 2-2-1-1-1 format, the team playing Game 1 at home has a 53.2% probability of winning the series (go here for the formulae I used to arrive at these numbers). If that team wins Game 1, their probability of winning the series suddenly increases to 66%, a boost of 12.8%, and if they lose, their probability drops to 34%, a decrease of 19.2%. Since there are only two possible outcomes in any game (win or loss), we can say that the average swing in series win probability for the home team in Game 1 is +/- 16% (12.8% plus 19.2%, divided by 2).

Do this for both teams and every possible situation in a 7-game series, and you can establish which games produce the biggest swings in series win probability:

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From 2008 to 2010, the NBA playoffs clearly had a "ruling class" that consisted of Boston, Orlando, and the Los Angeles Lakers. Combined, those three teams played 26 playoff series, and just once did one of them lose to a team outside of their own small clique:

Over that 3-year span, the Lakers-Celtics-Magic triad went 20-1 in series against non-ruling class teams, and as a result the road to the NBA title always went through one of the three teams. The rest of the league was largely irrelevant when it came to determining the championship.

Until this year, that is. For the first time since 2007, a ruling-class team failed to register at least 1 series win in a playoff season, as the Magic fell to the Atlanta Hawks in a 1st-round upset. Yesterday, the Lakers saw their season end against a non-ruling class team for the first time since 2007, losing in embarrassing fashion against the Dallas Mavericks. And the Celtics, for all of Kevin Garnett & Rajon Rondo's heroics in Game 3, still trail Miami's superteam 2-1 in their Eastern Conference Semifinal series.

It's tough to make any sweeping statements on the basis of a few week's worth of games, but the 2011 playoffs seem to indicate a major changing of the NBA guard. After having their way with the league's proletariat for three seasons, the once-mighty ruling class now finds itself on the wrong end of a radical upheaval.

This Heat-Celtics series is nothing if not a star-studded affair. A total of seven current All-Stars (Chris Bosh, LeBron James, Dwyane Wade, Ray Allen, Paul Pierce, Kevin Garnett, & Rajon Rondo) and 2 more former All-Stars (Jermaine O'Neal & Zydrunas Ilgauskas) have drawn minutes in the series so far. But how do those totals stack up to other playoff series since 1991?

First, let's look at the series that featured the most current All-Stars:

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Sports Reference's New Blog: Stathead

I have to admit that I find it very hard to follow all of the great research that people people are producing every day on the web. It's hard enough just checking the two or three largest sites, but when you add in team blogs, other stathead blogs and everything else, it becomes impossible. This doesn't even include trying to locate recent research in hockey, baseball, football and soccer.

So we've decided to do something about it. Every weekday, the Stathead blog will summarize the best research-related studies, news, conferences, and resources for baseball, basketball, football, hockey and soccer.

The blog will primarily be edited by Neil Paine and will typically feature 20-30 links to analytic content around the internet. We've been working out the format over the last two weeks, and we think you'll soon appreciate our concise summaries for all of the articles we write about.

Feedback as always is welcome.

What happens if you create power rankings using Jeremias Engelmann's 4-year Regularized Plus-Minus ratings (the most predictive version of APM) and each playoff team's distribution of minutes through two games?

Take a look:

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ESPN had an interesting news story today about Danny Crawford's history with the Dallas Mavericks in the playoffs:

NBA playoffs 2011: Referee Danny Crawford assigned to Game 2 of Dallas Mavericks-Portland Trail Blazers series - ESPN Dallas

The gist is this:

"The Mavs have a 2-16 record in playoff games officiated by Crawford, including 16 losses in the last 17 games. Dallas is 48-41 in the rest of their playoff games during the ownership tenure of Mark Cuban, who has been fined millions of dollars in the last 11 years for publicly complaining about officiating."

At the risk of running afoul of the Wyatt Earp Effect again, what is the probability that this has happened due to chance alone?

In his book Mathletics, Wayne Winston finds that the final margin of victory  in an NBA game can be approximated by a normal random variable with a mean of the point spread and a standard deviation of 12. Using that knowledge and the handy chart ESPN provided at the bottom of their story on Crawford, we can calculate the probability of Dallas winning each of their Crawford-officiated games since 2001:

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It was a banner weekend for underdogs, as the away teams kicked off the 2011 Playoffs with 3 wins, including victories by the Western Conference #8 and #7 seeds. How do the road teams' performances in this set of opening-round game 1s compare to other years since the playoffs expanded in 1984?

Let's take a look (all numbers from the perspective of the average road team in Game 1 of the 1st round):

(Click column headers to sort by each category.)

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