On December 26th, 2001, the Memphis Grizzlies hosted the Chicago Bulls. The Bulls missed over half their free throws (10-21). That’s a pretty rare and unusual thing! Throughout NBA history, free throw percentages have always been right around 75, and indeed in the 2001-02 NBA season specifically, the league-average free throw rate was 75.2 percent.
Yet in the Grizzlies’ next game a couple days later in Miami, their opponent, the Heat, once again missed over half their free throws (6-15). This is extremely rare territory. Only twice before in NBA history had that ever happened (in addition to once in 1947, in what was then the BAA):
And it was the first time in NBA history a team’s opponent missed over half their free throws in back-to-back games within the same season on a non-minuscule sample (the Nuggets’ opponent in each of those two games took a paltry nine free throws).
Three consecutive games of their opponent missing over half their free throws. Since, there have been another three instances of two consecutive such games, so even that’s remained incredibly rare. Three in a row when two almost never happens, much like the 2019 Nationals’ extra-base hit binge, is nearly unfathomable:
During that 2001-02 season, there was less than a one percent chance of a team missing over half their free throws in a given game:
And yet, here is the distribution of those 23 games:
Making it even more remarkable, it’s not even thanks to a small sample. Collectively, the three Grizzlies opponents shot 60 free throws, a very healthy number. They made only twenty-six (26) of ’em. That is just 43.3 percent.
In all of NBA history, not only has no one else had their opposition shoot even close to that poorly from the free throw line across any three-game stretch, but most of the (distant) runner-ups did so on smaller samples of opposing free throw attempts:
No one else is within 5.5 percentage points of them, and only the 1967-68 Sonics were the beneficiaries of their opposition collectively missing even half their free throws in as big a sample, let alone a percentage of just 43.3.
The 60 total free throws shot by the last three December Grizzly opponents were taken by 17 players:
Based on average NBA free throw rates, you’d figure there’d be roughly 75 percent as much blue there as there is red, representing about 45 made free throws out of the 60 attempts. But there is not. We know there is 43.3 percent as much blue as red.
Of course, while the average NBA player makes around three-quarters of his free throws, obviously some players are better than others. But this was not a product of a ton of free throws taken by horrible free throw shooters, or some sort of massive hack-a-ghastly-free-throw-shooter scheme at play. Right off the bat you can see Tim Duncan was the only player who attempted more than six free throws, and he was a near-80 percent free throw shooter that season.
Bruce Bowen was the only truly horrific free throw shooter involved, and he only accounted for two of the 60 combined attempts (having nailed one of ’em, he was one of the rare players whose free throw percentage this game improved). The other 16 all made around two-thirds or more of their free throws on the season.
We can work out, based on the number of free throws attempted by each specific player along with their respective individual free throw percentage from the entire season, the average likelihood of each of the 60 attempted free throws being successful, given the specific sample of shooters. That likelihood was 72.2 percent — only slightly below the overall NBA average.
Therefore, the raw number of those 60 free throws that the Grizzlies’ opponents in those three games would have been expected to make was, ironically enough, 43.3. In reality they made just 26.
While 43.3 is a low enough percentage that it’d be astonishing enough even if most of the 60 free throws were taken by Shaq and Dwight Howard, cumulatively this was tantamount to a 72.2 percent free throw shooter taking all 60 of those free throws and only making 26. It was a significant underperformance from nearly all 17 players.
Let’s underscore that by disregarding how good or bad each of the players generally was at shooting free throws, instead focusing solely on the comparison between their free throw performance in their late-December game vs. the Grizzlies and their overall free throw shooting proficiency for the full campaign.
For example, Tim Duncan took eight free throws. In the 2001-02 season, he was a 79.9 percent free throw shooter. That means we’d expect him to make about 6.39 of those eight free throws. Here are those figures, alongside actual made free throws, for everyone:
You’d obviously expect there to be about equal amounts blue and red there. But there is not. There is about 60 percent as much blue as red.
For each player, the blue subtracted from the red then represents how many points he left on the table. So with Duncan for instance, we know he would’ve been expected to make 6.39 free throws and that in actuality he made three. That means he left 3.39 points on the table:
The average player left over a full point on the table. Another way to evaluate it is how much worse each player’s free throw percentage was in that particular game as compared to their overall season free throw percentage. To use Duncan as an example again, in that game he took eight free throws and made three, which is 37.5 percent. With a free throw percentage on the season of 79.9, that means he shot 42.4 percentage points worse than usual in that Grizzlies game. Here are those figures for everyone:
So this was most certainly not a case of bad free throw shooters taking all the free throws and registering something resembling their usual badness. This was a sample of free throw shooters more-or-less representative of the NBA at large, just with nearly everyone doing way worse than they usually do.
No single result there — from an 80 percent free throw shooter like Duncan missing five of eight to guards like Rod Strickland and Steve Smith missing their lone attempts, and everything in between — is shocking. Afterall, from the perspective of each individual, it is merely one game. Oftentimes it’s mathematically impossible to not have a significant deviation in an individual game, depending on the number of attempts.
To use the most extreme example, if a 50 percent free throw shooter only attempts one in a game, his percentage for that game is either gonna be 100 or 0. No happy medium in that scenario exists where the player could shoot a percentage anywhere near his season rate. In other words it is literally impossible to not have large variance there.
But that variance is supposed to go both ways. For every player that shoots way worse in a game than usual, more or less there tends to be a player that shoots way better than usual; it’s the combination here that’s breathtaking. There has never been an imbalance even close to as extreme as that. Players during those three games against the Grizzlies shot an average of about 30 percentage points worse than they usually did that season. On average! Without a caveat of a small sample!
And a Memphis team that only won 26.6 percent of their other 79 games, won two of those three. They simply focused, watched the film, fine-tuned their strategy, and for a week had crafted and executed a magnificent free throw defense. Good work, Grizz.