This year's epic first-round playoff series between the Boston Celtics and the Chicago Bulls went seven games and included a total of seven overtime periods. "There were stitches, bloody towels, pain-killing injections, shoves, flagrants, technicals," wrote ESPN.com's Gene Wojciechowski after the final game on Saturday. Indeed, it seemed like the players on both teams were digging deeper than they had been through the six months prior. That's a familiar notion for many fans. In fact, the belief that NBA teams only go all out once they get to the postseason can be traced back at least three decades, to the film Airplane! In one scene, little Joey visits the cockpit and discovers that Kareem Abdul-Jabbar is the co-pilot. "I think you're the greatest," Joey says, "but my dad says you don't work hard enough on defense. And he says that lots of times, you don't even run down court. And that you don't really try … except during the playoffs."
It's probably human nature to try harder when the stakes are higher, so let's assume that Joey's dad is right, and NBA players don't give their best effort until the playoffs. Is there a way we could prove it statistically? We love to ponder questions like this at Basketball Prospectus.
There are a couple of obvious pitfalls in trying to quantify the effort of a professional basketball player. First, if it's true that players work harder in the postseason, then both teams should be equally affected, at least in the aggregate. Statistically, you're talking about what economists might call a zero-sum environment. That is to say, a team or player's gain or loss is canceled out by the gains or losses by the opposition. (If one player is trying harder on offense, then his opponent is trying harder on defense, too.) In the attempt to measure something as intangible as effort, this poses no small problem. Still, it might be possible to tease out some broad effects that show up nevertheless.
One thing we know is that the version of NBA basketball you see in the playoffs is slightly different than what you see in the regular season. The pace is slower. Since the ABA-NBA merger in 1976 (which happened to coincide with the league's decision to track all the numbers needed to calculate possession-based statistics), playoff games typically average between three to five possessions fewer than they do during the regular season. Teams are also more careful with the ball: On a per-possession basis, turnovers decrease by a little more than 5 percent. Finally, teams are less prone to settling for outside shots. You can see this effect numerically by the increase in fouls drawn—the ratio of free throws made to field goals attempted goes up by almost 7 percent in the playoffs.
These numbers don't in themselves suggest that teams are playing harder. Some of the changes can be explained by the types of teams that make the playoffs in the first place: Maybe the clubs that take it slow and attack the hoop tend to win the most games during the regular season and advance farthest in the postseason.
How to address such a murky question? Let's invent a new statistic! Basketball analysts love to do this, in part because, like astronomers, we get to name our new discoveries. In this case, we'll name our new metric after the player who best typifies the hustle-over-talent ideal: We'll call it RAMBIS.
First, we need to decide which statistical categories are the most "effort-based," so we can figure how to combine them into a RAMBIS number. This isn't an easy task, since lackluster effort would show up throughout the box score. However, after some hand-wringing and linear-regressing to determine which statistical categories changed the most from the regular season to the playoffs, we settled on four team measures—two based on offense and two based on defense.
The first number, offensive rebound percentage, refers to the number of offensive boards grabbed compared with the number of offensive rebound opportunities available. In theory, offensive rebounding requires increased effort because players have to work to get around opponents that have inside position on the boards. (Maximum-effort players like Moses Malone and Dennis Rodman are remembered for their relentless work on the offensive glass.) Next we considered the number of free throws made per field goal attempted, a common way of measuring a player's foul-drawing ability. This should be higher when guys are forgoing easy jump shots and putting in the extra oomph to drive to the hoop. Third, we looked at the opponents' effective field-goal percentage—that's just like the regular field-goal percentage but tweaked to account for three-point shots. And finally, we tallied up the rate of forced turnovers per possession.
So how do you combine those numbers into a single statistic? We'll omit the hairy math, but we balanced out the four categories to put them on equal footing, added them up, and rounded off the sum. According to this calculation, the hardest-working team in the NBA playoffs (since the merger, at least) would have been the '77 Bulls, with a 231 RAMBIS. That's apropos, because the Bulls in the 1970s, led by Norm Van Lier, were a bunch of bruisers. At the other extreme, the '83 Super Sonics managed a RAMBIS of just 147. (Both teams wiped out in the first round.)
The real question, of course, is whether a team's RAMBIS rating goes up during the playoffs. This year's Celtics had a regular-season RAMBIS of 188; the Bulls had a 185. During their epic seven-game playoff series, their RAMBIS ratings registered at 185 and 182, respectively. Oh well.
In fact, if RAMBIS really does measure effort, then we might conclude that the average team tries less hard when the stakes are higher. Since 1977, playoff teams have seen their RAMBIS numbers decrease by an average of 4.5 percent from the regular season. Less than a quarter of all teams boosted their RAMBIS on the big stage. This is consistent with at least one of our original observations about the differences between regular-season and playoff basketball: If teams are trying harder, they're also being more careful. Forcing turnovers certainly seems like a function of effort, but so does avoiding turnovers. (If we drop turnovers from the equation, the RAMBIS might be a bit better, with the average score going up very slightly during the playoffs.)
RAMBIS might not give us much information on whether teams try harder in the playoffs, but it's still useful. Teams with high RAMBIS tend to share a style of play—they crash the offensive glass, eschew jump shots in favor of driving the basket, and work a pressure-based defense. They're also consistent in the metric from one season to the next. Curiously enough, many of those teams seem to have been coached by Hubie Brown. Teams with low RAMBIS are also similar stylistically—and sometimes have great success. The San Antonio Spurs of recent vintage turn out to have an appalling RAMBIS, but that's not from lack of effort. Gregg Popovich's defensive system places little value on creating turnovers and denies perimeter players the opportunity to go for offensive rebounds. As four championships will attest, the anti-RAMBIS approach works.
We also calculated a RAMBIS rating at the player level, using blocks and steals in lieu of opponent effective field-goal percentage and percentage of turnovers forced, but there wasn't any discernible "effort" trend there, either. The players who upped their career RAMBIS results the most in playoff time include Isiah Thomas (+45.1), Dirk Nowitzki (+39.0), and—listen to this, Joey—Kareem Abdul-Jabbar (+36.0). Other noted playoff heroes also fare well, like Michael Jordan (+23.1) and Dennis Rodman (+26.1). But before we get too excited, we have to pay attention to the laggards on our leaderboard. Moses Malone (-87.1) is dead last. Patrick Ewing (-52.8) is next to last. Both players were lunch-pail types who reached Hall of Fame levels based on hard work and consistent effort.
We tried lots of variations on RAMBIS in hopes of putting numbers with our idea that players are working harder in the playoffs. Nothing worked perfectly. Maybe, in the end, it's not that the players are trying that much harder but that we're watching that much more closely. The stakes are higher. The drama is heightened. The action gets chippier. One measurable effect this year is that technical fouls per game have increased from 0.67 in the regular season to 1.27 in the playoffs. So while the players may or may not be trying harder, they certainly seem to be displaying more emotion. Is that the effort effect we've been searching for, or are officials just working harder to keep control of the action? We could go around like this forever, so perhaps the best course of action is just to trust our eyes and appreciate what we see.