When the San Antonio Spurs used an 11-0 run inside the final minute to defeat the Boston Celtics on ABC in early February, the narrative held that it was the latest example of the Spurs' veteran presence making the difference in a close game. While the final score ended up six points, outside the range, at the time San Antonio was a league-best 14-4 in games decided by five points or fewer. Considering we also found out earlier this week that the Spurs are the league's most senior team, the connection between experience and performance in close games is easy to make.
To explore that possibility and more about close games, I got Basketball-Reference.com's Justin Kubatko to update the data on games decided by five points or fewer. I used for a study on Supersonics.com two years ago. Now I've got eight years' worth of stats to draw from, including this season. Using the final margin is not a perfect indicator because of situations like the Celtics/Spurs game where one team pulls ahead or rallies in the final minute, but at the season level it does a fine job of reflecting team performance in close games.
Let's start by taking a look at how teams have fared in close games this season.
Team CW CL Win% Team CW CL Win%
Dallas 11 3 .786 Oklahoma City 3 14 .176
Orlando 10 3 .769 Sacramento 5 13 .278
Miami 13 4 .765 Charlotte 6 15 .286
San Antonio 14 6 .700 Golden State 5 12 .294
New Orleans 10 5 .667 L.A. Clippers 4 9 .308
While the worst five teams in close games include many of the league's weakest teams overall, the list of best teams in close games contains some surprises. None of the league's top three teams (Boston, Cleveland and the L.A. Lakers) have done especially well in games decided by five points or fewer, winning between 60 and 65 percent of those contests. San Antonio has done very well in close games despite losing their last two with margins under five points, but three teams have superior records (the Spurs have in fact won the most close games of any team). Dallas and Miami in particular have relied on close wins to boost their records, a reason both have overperformed their point differentials.
Oklahoma City's bad luck in last-second finishes is no surprise to anyone who has followed the Thunder this season. Time and again, Oklahoma City has been done in by buzzer beaters, including multiple occasions where Kevin Durant has scored to put the Thunder ahead in the closing seconds only to see an opponent match his shot. In fact, Oklahoma City's futility in close games is historic. No other team in the sample has won less than 25 percent of its close games. Presumably, things will even out to some extent the rest of the way.
Let's turn to the larger eight-year sample. A first good cut at the data is to look at teams' performance in close games as compared to their performance in games decided by more lopsided margins. Here's what that looks like, with 2008-09 teams in red.
The trend is fairly evident looking at the chart. Better teams definitely tend to win more close games than weak ones, but the relationship is hardly perfect. The correlation is just .454 (a correlation of 1 or -1 means two variables are perfectly in sync, while a correlation of 0 means no relationship whatsoever). There are two extreme schools of thought on close games--those that believe they are primarily decided by luck and those that feel they are primarily decided by teams and demonstrate their true ability. Neither position is supported by the data.
Instead, what the results tend to show is that the difference between good teams and bad teams is mitigated in close games. Look at the best-fit regression line on the chart. The slope is nowhere near 1, and the difference between the expected record in close games for the very best teams (about .600) and the very worst teams (about .400) is much smaller than the difference between them in games that are not decided down the stretch.
When you think about it, this makes perfect sense. Say you were coaching (or cheering on, if you prefer) an underdog team playing a powerful opponent. If I gave you the opportunity to advance directly to the final five minutes of a close game, even if you were trailing by a couple of points, you would take that scenario because anything could happen over the shorter period. The same logic can be applied to explain why we see more upsets in the one-and-done NCAA Tournament than in the NBA's best-of-seven postseason. The smaller sample draws all teams toward .500.
Let's reframe the discussion in a different context by taking a look at the best teams in close games in comparison to their overall performance. We can use the regression line from the chart above to predict what percentage of its close games a team should win based on its record in non-close games. Who are the biggest overperformers and underperformers?
Team Yr CW% PCW% Diff Team Yr CW% PCW% Diff
Sac 02 .875 .571 +.304 Ind 06 .267 .546 -.280
NJN 08 .727 .439 +.288 NJN 03 .286 .555 -.269
Mia 09 .765 .480 +.285 OKC 09 .176 .432 -.256
Dal 09 .786 .517 +.269 Cha 09 .286 .503 -.217
Por 08 .737 .480 +.257 LAC 05 .300 .515 -.215
Let's use last year's Nets as an example. They won games decided by more than five points at a .300 clip, which means we'd project them to have a .439 winning percentage in close games. Instead, their actual .727 winning percentage was .288 higher. Don't underestimate the importance of winning close games. The Bobcats this season illustrate how critical games decided by five points or fewer can be. Had Charlotte fared as well as expected in these games, the Bobcats would have an extra four or five wins (10-11 or 11-10 vs. 6-15). Give them four more wins and they go from tied for 11th in the Eastern Conference all the way to percentage points ahead of Philadelphia for the seventh seed.
The high number of teams on these two lists from the current campaign is also noteworthy, and I think it can be explained by the fact that things will shake out a little bit more over the final month and a half of the season.
In the big picture, the question worth asking is this: What differentiates teams that perform better in close games than we would expect from those who struggle? The most obvious potential answer is age, especially after we recently found a relationship between a team's effective age and its overall success. Using that same data, here's team age plotted against close-game performance:
See any pattern there? I don't, and neither does a test for correlation (.067, which is minimal at best). Conventional wisdom has it that veterans like the Spurs' are better equipped with the mental fortitude to handle close games than young teams, but this doesn't show up in the numbers. Look back up at the leaderboards. None of the teams that overachieved in close games had an effective age of more than 30, and last year's Blazers (effective age 24.8) were one of the youngest teams in the entire sample. The underperformers tended to be a little younger as a whole, but the two most extreme examples (the 2005-06 Pacers and 2002-03 Nets) were both average in terms of age, and they had extensive playoff experience including a Finals appearance for the Nets.
I'm picking on age a bit unfairly here, because running the same test with other potential factors (Offensive and Defensive Ratings and pace) also fails to uncover a relationship of any strength. Why not? The most intuitive answer comes from another look at the numbers--how teams fared in close games compared to their expected records in successive seasons.
Again, there is no apparent relationship, with a correlation of almost precisely zero. A team that outperforms its expected record in close games is not necessarily more likely to do so again the following season than one that underperformed. Here, the Spurs are an interesting example. Last year, San Antonio was 11-9 in games decided by five points or fewer, and in 2006-07--when the Spurs won the championship--they went 8-11 in such contests. The year before, San Antonio went 14-5. The Spurs have had the same coach throughout this period and a similar roster, yet there is no rhyme or reason to their record in close games.
What this tells us is that we should not read much, if anything, into a team's record in close games. There may be some teams that are better equipped to win tight games for reasons that go beyond their overall ability, but we simply can't tell them apart from the pack because the sample sizes are too small.
Kevin Pelton is an author of Basketball Prospectus.
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