How Do the Boston Celtics Keep Winning Basketball Games?

Surprisingly, the Boston Celtics are in a three-way tie for the East's 7 seed and have a legit chance to make the postseason. What's going on?

We're about one month away from the end of the NBA season, and somehow the Boston Celtics are in the hunt for a playoff spot in the Eastern Conference. No, that statement is not the result of some St. Patrick's Day hangover hallucination -- the team with the leprechaun logo, that everyone penciled in as a 2015 lottery team long ago, is actually knocking on the door of the postseason in mid-March.

Yes, this is the same team that traded away both its top scorer in Jeff Green and top distributor in Rajon Rondo by midseason, and it's the same one that lost its top rebounder and one of its brightest young prospects in Jared Sullinger to a season-ending foot fracture by the All-Star break. When those kinds of headlines stand as the top stories of the season for a rebuilding franchise, rarely are they then followed by analysis of winning streaks and playoff race columns.

Yet, here we are. The Celts are winners of five straight and 10 of their last 13. They're in a three-way tie for the 7 seed in the Eastern Conference with the Indiana Pacers and Miami Heat, and are relegated to the 9 seed simply because the necessary tiebreakers have yet to be resolved (more on that in a minute).

The Celtics and the Eastern Conference Playoffs

The race is now realistically down to four teams for those final two spots, and here's how our algorithms project their final records will play out, along with how we project their playoff chances:

TeamCurrent W-LGBProj. W-LPlayoff Liklihood
7Indiana Pacers30 - 36-37.8 - 44.260.4%
8Miami Heat30 - 36-37.5 - 44.647.0%
9Boston Celtics30 - 36-37.3 - 44.743.7%
10Charlotte Hornets29 - 371.036.9 - 45.143.1%

The Pacers, Celtics, Hornets, and Heat (in that order) all have difficult remaining schedules, according to John Schumann at At the moment, every season series combination between these four teams sits at 2-1, with one game remaining (all of which will be played between March 25th and April 7th). How those games play out will go a long way in determining which of these teams make the playoffs, since neither of them is defending for a division title and head-to-head records are the subsequent tiebreaker (with records against Eastern Conference opponents coming after).

In short, anything can happen over these last few weeks of the season, and either of these four teams could take one of those last two spots. And that's all without even mentioning the Brooklyn Nets, who only sit 2.5 games back of seventh (although we only give them a 7.7% chance of overcoming the four-team logjam and getting in).

So, what is the factor that has helped the Celtics win all these games? Can they keep it up and really make the playoffs?

Is It Team Efficiency?

At 10-3 since February 23rd, the Celtics have the fourth-best winning percentage in the Association for that period (tied with Golden State and trailing the Jazz, Hawks, and Blazers in that order).

Usually, when a team makes that kind of unexpected surge from the bottom of the standings, there are certain trends you can find in the team's numbers if you go digging around.

For example, maybe there's some kind of huge spike in their offensive or defensive efficiency metrics associated with the jump.

RecordOff RtgNBA RankDef RtgNBA RankNet RtgNBA Rank
First 5320-33100.823rd103.315th-2.519th
Last 1310-3102.413th98.96th3.510th

Sure, those leaps of about ten spots are notable, but the Celtics are still putting up pretty average offensive numbers and a pretty low Net Rating for a team that has the same record over that span as the Golden State Warriors (second in Net Rating at 9.4). The jump in Defensive Rating is likely a big culprit, but the Milwaukee Bucks went 3-9 over the same span with the exact same level of defensive efficiency. So if the offense is average and the defense isn't that killer, how are they doing it?

Is It the Players?

Maybe a player (or more) has gone absolutely bonkers over that span? Well, not really.

Newly-acquired sixth man, Isaiah Thomas, has averaged 21.4 points, 2.7 rebounds, and 5.4 assists per contest in his 10 games in Celtics green, but he's missed the last four games in their five-game winning streak. He can't be the whole reason.

Other than that, no one's even averaging 15 points per game (Avery Bradley is closest at 14.9).

Is It Hot Shooting?

Of the top-six shot takers for the team, only one of them is shooting over 41% (and Brandon Bass, the player in question, takes more than half of his shots directly at the rim).

Isaiah Thomas96.215.340.6%
Avery Bradley106.114.940.9%
Jae Crowder134.210.539.7%
Brandon Bass135.710.454.8%
Evan Turner133.89.540.7%
Marcus Smart133.29.433.6%

Even promising sophomore Kelly Olynyk has had a horrible shooting split of 31.0% from the field, 24.0% from deep, and 56.3% from the line in the eight games since his return from an ankle injury.

Gross. Just gross. Much like the team's overall shot chart:

I mean, they're shooting below the league average in every single area but the left corner three, and that only accounts for 3.4% of their shot distribution!

OK, so the team isn't all that efficient on offense, is decent enough on defense, hasn't had their best scorer for four games, and is shooting pretty poorly overall as a team (26th in the NBA with a team mark of 42.4% over that span). On top of that, almost all of their main rotation players are shooting below average marks from the field. Still not a recipe for success.

Is It a Particular Lineup?

Maybe a certain lineup is really clicking?

Well, their most used lineup of Marcus Smart, Bradley, Evan Turner, Bass, and Tyler Zeller has posted a putrid Net Rating of -21.6 (from an Offensive Rating of 87.0 and Defensive Rating of 108.5) in 109 minutes during those 13 games. That's more than triple the time logged for the next most used lineup -- the same thing, but with Jae Crowder replacing Bradley, who missed three games in the middle of this run.

Sure, there have been more effective lineups that have balanced things out, but it's pretty glaring when your most used lineup (by far) is also your least efficient (by far), and you still manage to go 10-3.

OK, not the offense, only partially the defense, not any one player, not hot shooting, certainly not a clicking lineup.

Was Their Schedule Just Plain Easy?

That's not really it, either.

Eight of their last 13 opponents are currently vying for a playoff berth, and one of the remaining five opponents was the Utah Jazz -- arguably the best team in the league since the All-Star break (no, really). You can forgive losses to the Cleveland Cavaliers and Golden State Warriors, while the only wins of the 10 we're discussing you could take away for the opponents being "weak" are those against the Orlando Magic, New York Knicks, and Philadelphia 76ers. Everything else? Quality wins against quality opponents.

I Give Up, What Is It?

Honestly, it's hard to say what it has been definitively beyond good coaching. Brad Stevens has taken a roster filled entirely with players that would be nothing more than a seventh or eighth man on a contender and somehow made them collectively competitive (seriously, Jonas Jerebko has been a difference-maker off the bench).

When the aforementioned respectable defense hasn't been enough, the Celtics have relied on solid ball movement and sharing the load. Over this 13-game span, the Celtics have been sixth in the league in assist percentage (62.7%) and first in turnover ratio (12.5 per 100 possessions). That has resulted in a league-leading 1.94 assist-to-turnover ratio for that span. The shots might not all be going down, but they're certainly looking for their best options.

Is Any of This Sustainable?

When teams go on uncharacteristic runs, they're usually a product of hot shooting, players performing over their usual level, a clicking lineup, or an easy schedule. Since the Celtics haven't really benefited from either of those things, and have instead relied on defensive identity and ball movement, it's hard to predict when or even if a regression to the mean is coming.

By subtracting guys like Rajon Rondo (nERD of -5.5) and Jeff Green (-0.2) (relatively inefficient mid-level performers that were being treated like alpha dogs), the team unexpectedly got more cohesive and, in turn, better. They may not be setup to be a Cinderella contender come playoff time, but the pieces are certainly fitting together just well enough to get them into the playoffs in the Eastern Conference. Once there, perhaps they could be a feisty enough 7 or 8 seed to give a top team a proverbial run for their money, all while gaining valuable postseason experience for their young core in the process.

Since their lottery odds are getting worse by the day anyway, why not go for it?

The schedule is filled with opportunity over the next few weeks, when tiebreakers will be decided and the playoff picture will be finalized. Let's see if the Celtics have enough of the luck of the Irish to make it happen.