Why do computers have such a high chance of a Celtics title?

The Boston Celtics are a force to be reckoned with. They have the best points difference and defense rating in the Eastern Conference and can boast the best conference record since the turn of the season on January 8. In the last month, they have beaten the 76ers by 48 points, the Heat by 30, and the Nets by 35 and 23.

The Celtics are also an enigma. Despite all their strengths, they also rank 18th in the offensive rankings, per Cleaning the glass, and the Pistons and Pacers recently gave up. With less than a quarter of the regular season before the game, they are sixth in the East, closer to the playoffs at the top of the standings.

Yet, despite this ambivalent summary, projection systems believe in Boston’s potential. The bellThe NBA odds machine gives the Celtics an 11 percent chance of winning the title, and we’re not alone: ​​the Basketball-Reference sets the odds for the Celtics Championship at 9 percent, ESPN at 13 percent and FiveThirtyEight with an astonishing, league-leading 17 percent.

Boston’s recent momentum and subsequent hopes for predictions are based primarily on the team’s defense. The defense doesn’t actually win more than a playoff attack, but Boston’s defense is out of the norm. During the Celtics series on January 8, their defense was an incredible 4.2 points per 100 possessions better than the next best defense; second place Heat are as close to 14th place as first, per CtG.

The league has come up with value switching as a means of slowing down off-screen offensive kits, and Boston is offering a prime example of this style of defense. The Celtics include 40 percent of rivals, the highest score in the league, according to data from Second Spectrum. (Miami is 39 percent; no other team is over 33.) And they only allow 0.86 points of possession when they change the screen – the most expensive rating in the league.

Boston benefits from incorporating elite individual defenders into this broader team concept. The Seven Celtics have played tough minutes after the exchange deadline and all are at least average in defense, with several ratings among the league’s most influential defenders this season, according to the projected plus-minus.

They even cleared their propensity for fouls: before January 8, the Celtics were still the top five teams in defense, but ranked only 18th in the opponent’s free throw percentage. CtG. But the Celtics improved to fourth in the percentage of free throws from the opponent after that moment.

The return of Marcus Smart from injury and the addition of Derrick White, a former Spurs, through trade aid. But the most obvious change that could help explain the Celtics’ current form comes from the deployment of Robert Williams III by rookie Name Udoka, who defends about half the number of screens he had earlier in the season, according to the analysis. of data from the Second Spectrum.

Instead, the Time Lord often plays a free role in safety, nominally guarding an undamaged player from the perimeter while Al Horford or another teammate takes the lead on the screen. So Williams – who ranks third in the league with 2.2 blocks per game – can move to deter any attempt at the edge. Note that before deploying 7 and 6 feet in all the plays in this video, Williams kept a non-shooting wing like Tori Craig or CJ Eleby, not the opponent’s best goal.

Or check out the best example of Boston’s late victory over Denver in mid-February. Instead of facing Nikola Jokic, Williams takes Aaron Gordon, while Jaylan Brown takes over the current MVP. After the switch forces the little white to Jokic, Jason Tatum doubles, opening a ribbon to the hoop – just so Williams can transfer, erase the laying attempt and help seal the Celtics’ victory.

(Aside: the last playoffs didn’t offer much in the way of strong defensive battles; in the last five postseasons only six teams have won less than 90 points. And yet between Boston and Cleveland, Miami and Toronto, this year’s Eastern playoffs The conference can bring defense back to highlights on the schedule, with teams showing stylistic diversity in how exactly they keep teams from scoring, from switching Boston and Miami to Cleveland’s three towers to Toronto’s 6-foot 8-wing fleet.)

But despite all their defensive power, the Celtics’ profile still has some flaws. Boston’s record falls by 5.6 wins less than we would expect based on the difference in points, according to CtG, which is the biggest difference for any playoff team, and the culprit is the problems in the upcoming matches. Boston is only 11-18 in clutch games (defined by NBA.com as games within five points in the last five minutes).

Usually good teams in all games are also good in the clutch and vice versa. The 11 teams with the worst records in clutch situations this season include Boston and the 10 teams with overall loss records.

But this discrepancy should not be a problem in the future; with rare exceptions, past clutch characteristics are not predictive of future clutch characteristics. The correlation between the regular season victory rate and the post-season clutch victory rate is negative -0.05, among teams with at least five playoff matches from the 2010-11 season – or generally zero, meaning there is no significant correlation. (Looking at all playoff teams in this period, even those with only one playoff game, the correlation is still a small 0.14.)

The Bucks 2020-21 had 13-15 in regular season games, then 7-2 in the playoffs on the way to the title. The 2019-20 Heat were 18-18 in regular season games, then 11-3 in the playoffs. 2011-12 76ers had the worst performance in the regular season among all teams for the playoffs in this period, with a score of 7-20 – then finished 6-2 in the playoffs.

Even if their clutch fights even in the coming weeks and months, the Celtics’ attack remains a real concern. They are still struggling to score in one of the two most lucrative areas of the court: they rank only 26th in terms of edge strikes, CtG, and although they take a healthy amount of 3 points, they don’t actually do that much. For the context of this chart, the average accuracy of 3 points this season is 34.9 percent. This means that only one of the seven most used players of the Celtics is even at the middle level. (Josh Richardson, sent to San Antonio in exchange for whites, was 39.7 percent with 3.5 long attempts to play.)

Boston’s shooting problems are compounded by the lack of a central playmaker. The Celtics do not have an offensive engine like most other contenders, which is why Tatum led the team, but ranked only 52nd in the league in points created in 36 minutes when we measured the numbers in January. His assist rate has not changed since last season. In the same way, Tatum leads the team in possession, but ranks only 45th in the league, according to NBA Advanced Stats (minimum 10 games played).

Rather, the Celtics have a number good passers-by – including especially their great ones – but no great creators in a half-court setting. They have to work hard to generate open frames, and when ping-ping-ping sequences do not align exactly, they often end up with lower insulation quality. They rank fourth in the frequency of isolated games, but do not score nearly as effectively as teams such as the Nets (which are first in isolation frequency) and the Bucks (third). Tatum, the team’s only All-Star, is ranked 12th out of 18 players with at least 150 iso this season – not terrible, but not the kind he needs this offense.

More enthusiasm in the transition would help, and Boston has cheered up a small sample since trading for White. Before the deadline, the Celtics added 1.4 transition points per 100 possessions, on CtG, which ranked 27th; after the deadline, they reach seventh place with 4.3 transition points added.

If there is an additional warning sign under the radar for the team, it is that the defense may not be as indomitable as it seems, thanks to a great deal of luck in shooting. Boston’s opponents have not met their expectations of shooting – based on factors such as the location of the shot and the distance of the defender, from the Second Spectrum – with the biggest difference for each team. The difference is especially large during Boston’s sharp rise in the standings: as of January 8, the Celtics’ opponents have an effective flight percentage of 3.3 percentage points worse than expected, while the next team on the list is only 0.8 percentage points below.

Thanks to his scheme and individual talent, Boston’s defense still needs to be one of the best in the league, even if this state of luck does not continue – but given the Celtics’ tendency towards offensive stagnation, it may be necessary to be the best, point, the team to keep its promise. Pistons 2003-04 are a historical anomaly for a reason; not many teams win the title solely because of their dominance in defense.

The projection systems are liked by the Celtics both because of their high differential and because of the talent on their list; FiveThirtyEight, in particular, is in love with the rotation of the Celtics. Of course, with such fierce competition in the East, even computers think they have a much better chance of losing in the first round (37 percent chance, according to our odds machine) than winning the title (11 percent chance). And yet, because the field looks so wide open, Boston can really have one of the best chances in the group.

In the end, the Celtics are able to beat anyone: According to CtGThe Celtics have the best net rating in the league (plus 4.9 points per 100 possessions) against opponents who rank in the top 10 by points difference. For a team that was 18-21 recently, with growing concern about the combination between its two stars, even a 1 to 10 chance in the finals marks a huge leap in the right direction.

Statistics for the entire league until the matches on Sunday.