The Algebra of the Game: Overtime & the 3FG

When play was interrupted a fortnight ago, NBA ’19-20 had delivered 971 (of a scheduled 1,230) games and 46,938 minutes of “basketball battle,” as legendary Celtic radioman Johnny Most might have dubbed it. The average game performance featured 111.4 points on 100.9 possessions, with a FG% of .460 (.357 for three-point attempts). Our “Team Average” attempts 34 treys and 23 FT’s per game, while committing 14 or 15 Turnovers and grabbing 10 Offensive Rebounds.

This “seasonal” data is virtually identical to the league figures from the ’18-19 campaign – indeed, the OR and TO numbers as well as the shooting rates vary very little from the data of TEN years ago.

The usage of the three-point shot did continue its upward trend this season, per-game attempts increasing by two and 3PAr elevating from .359 to .382 since just last season. (3PAr in 2009-10 was .222, per-game 3FGA’s a mere 18.)

“Bonus Basketball”

Exactly 330 of those 40-some thousand minutes of NBA competition this season occurred after the conclusion of Q4. On 61 occasions, a ballgame extended into Overtime, five of them requiring a second session to determine a winner.

To what extent, do you suppose, does the “quality” of OT play compare to performance in the First 48? Legendary players – the studs – tend to “step it up” under such circumstances, but most players … hmm?

The added pressure of OT drops FG% to .414 and 3FG accuracy to .305, while 3FG usage rises to .402. On average, a team commits 1.2 Turnovers and grabs 1.4 Offensive Rebounds per-OT period (which converts to roughly 11.5 TO’s and 13.5 OR’s per-48 minutes).

Curiously, familiar surroundings have absolutely no effect on FG shooting once OT kicks in. Home teams made 230 of 555 FGA’s, visitors 233 of 563 (.414 in each case) … hardly a surprise, then, that the locals were just 33-28 (.540). [For the partial season, overall Home Court Advantage calculated to .551 (535-436).]

Two out of three (40 out of 61) OT contests are decided by five points of fewer – even though the average margin of victory in OT games this season is 4.9 points. [OT Winners outscored Losers 853-552, roughly a 14-9 edge per game.]

Winning teams committed 74 Turnovers, the losers just 11 more; and those losers won the Offensive Rebounding battle 95-94 … but the victorious side held whopping advantages in Points off TO’s (120-62) and Second-chance Points (128-63). Add in a more than 2-to-1 edge in FT’s (244-98), FTA’s (310-133) and Free-throw Conversions (142-60). [TO’s, OR’s and FT’s account for 269 of the 301-point scoring difference between OT winners and losers.]

The victorious posted 1.318 Points-per-Possession, the vanquished 0.848. Consequently, in shooting accuracy, the winners’ FG% was .505 to the losers’ .334 -- .443 to .211 from 3-point-land.

Losing squads took 44.7 percent of their shots from behind the arc, compared to a 35.0 percent “long-bomb” rate for their opponents.

Playoff Pressure + Overtime = ??

OT play in recent NBA Post-seasons has indeed provided us a few thrills – in a variety of ways. Just last season, Portland and Denver staged a four-OT marathon in Game 3 of their Conference Semi-Final … while during the opening round in 2014, the Thunder and Grizzlies needed an extra session to determine a winner in FOUR of their seven match-ups, while the Blazers and Rockets went to OT in three of their six outings.

During the post-seasons of the 2010’s, 53 games needed OT, producing 63 extra sessions. Here’s the cumulative data:

FG: 417-1058: .394
3FG: 82-338: .243
3PAr: .319
FT: 309-393: .786 [177 FT Conversions]
TO: 168 [-191 points]
OR: 185 + 28 (team) [+215 points]
DR: 394 + 47 (team)
Poss: 1189
Points: 1225 [1.030 per possession]

The Algebra of NBA Over-time Competition, circa 2020
NBA Playoffs Thru the Years: The How's and Why's
It takes some balls to shoot THAT many threes