Five key trends that are shaping the 2021-22 NBA season

A quarter of the season is already over. Around this time, some statistical trends begin to stabilize and we can begin to learn (and perhaps predict) how the rest of the year might shake out. 

Here we take a closer look at some of the on-court and betting trends that have defined the 2021-22 NBA season so far.

5. Free throws are way down

There was justifiable skepticism that the promise to eliminate non-basketball plays would take hold after their adoption by the NBA Competition Committee in the offseason.

After all, there seems to be a point of emphasis on illegal screens every other year, and then you look up in the playoffs, and bigs around the NBA are pulling stuff that would Kevin Garnett blush.

But through at least 20 games, the enforcement has been consistent and the effect has been profound.

To illustrate just how dramatic the drop-off has been, at .175 free throw attempts per shot attempt, this would be the lowest amount of free throws taken as a fraction of the offense since the first year of the BAA in the 1946-47 season.

NBA players are already adapting their games and finding new ways to generate foul shots (welcome back, James Harden), but it’s clear the new rules are driving down free-throw attempts.

4. Teams are taking fewer shots at the rim

For the 25th consecutive year, teams are taking more 3-pointers this year than in any season prior. But the funny thing is, the analytics crusade to eliminate the dreaded "long 2" has largely been won. Mid-range attempts are static this year compared to last, at 30.6% of all shot attempts.

Instead, the new high watermark of 37.2% of all shots that come from 3-point attempts is pulling from an unlikely place — attempts at the rim.

This season, 32.1% of all shots are coming at the rim, compared to 33.3% in 2020-21 and 35.2% in 2019-20.

Open layups and dunks are still the best shots in the NBA, but teams are having a harder time generating those looks than in years past.

The ideal, of course, is to use the threat of the 3 to pull the defense from the basket enough to allow those shots at the rim — this is the reason Steph Cury never stops moving on offense.

But it seems defenses are more content than ever to live with 3-point shooters springing free than leaving the basket unprotected for any reason.

3. The Warriors and Cavaliers beat the spread

If there was an award for a team that was most likely to make you money this season, the winners from either conference would clearly be the Golden State Warriors in the West and the Cleveland Cavaliers in the East.

Even after their loss to the Phoenix Suns on Tuesday, the Warriors have been dominant against the spread this year. They are 15-5-1 ATS, and 4-1 in their last five games, and have an average point differential of +7.2 against the spread, per Cleaning the Glass.

Not only are they winning, they’re relieving some heartache for Warriors bettors by doing it handily.

Even more surprising is the similar dominance of the Cavaliers, with their lineup of Jarrett Allen and rookie phenom Evan Mobley. Cleveland is a sterling 14-5-2 against the spread and 4-1 in their last five games, with a +6.1 average point ATS differential.

To put those numbers by the Warriors and Cavaliers in perspective, the third-best spread differential this year is by the Miami Heat, with +2.9.

The safest money in the NBA this season has been betting Golden State or Cleveland to cover.

2. The Nets defense is suspect

Team defense is a hard thing to accurately gauge in the NBA, with no all-in-one metric truly capable of telling the whole story.

Sometimes a team plays perfectly and the opponent still scores, other times sloppy play is rewarded by an inexplicable miss. But location expected field-goal percentage can provide insight into which teams might be getting luckier than others.

Cleaning the Glass’ location eFG% measures if the team in question shot the average field-goal percentage from each shot location, using their shot profile to determine how healthy their shot diet is.

Conversely, defensive location eFG% measures if a defense allowed the average accuracy from every spot on the court, how well would opponents score? The difference between a team's actual eFG% and their location eFG% can be a strong indicator of who is benefiting from (or being harmed by) shooting luck.

This season, there’s one clear runaway beneficiary so far: Brooklyn. The Nets allow the lowest eFG% in the NBA at 49.5%, more than 2 points below league average, and 3 points below their location eFG% of 52.7%. 

Context is still important here, as some teams deliberately encourage attempts at the rim because they have shot-blocking centers capable of making a play (think Cleveland or New York), and they earn the difference between their location eFG% and their actual eFG%. But in Brooklyn’s case, they really are just getting lucky — and there’s no reason to expect it to continue.

1. Unders have been king

Perhaps not surprisingly, given a few of the other trends we’ve already highlighted, playing the Under has been a winning move so far this season. 

Of all 314 games played to date, the Under has hit in 56.4%, per Covers.com.

Team offenses are down league-wide, in part due to the drop in free throws, but also due to shooting returning to closer-to-normal levels after last year's offensive explosion.

The 2020-21 season is looking more and more like a statistical outlier, from an offensive standpoint, and odds have been slow to adjust to reflect the new reality.

However, team offense also tends to improve as the year goes on, so pouncing on any perceived overcorrection by oddsmakers and betting Overs again could soon be the right call.