Blocks & Contested Blocks
Box-score blocks plus a contested-block count that catches the near-blocks — a fuller picture of rim protection than the blocks column alone.
Credit: CountingStatistics toolkit
Why it exists
A box-score block is a clean, unambiguous event: the defender made contact with the ball and altered or rejected the shot. What the blocks column misses is everything that happened right next to it. A player who contests 12 shots at the rim and blocks 3 of them deterred the other 9 as well. The shooter knew a help defender was there. The driver chose a different angle. The offensive player rushed the shot. None of that shows up as a block.
Contested blocks — the count of possessions where a player was recorded as a primary rim contestor on a shot attempt that wasn't fully blocked — gets closer to the true rim protection picture. Together, blocks and contested blocks give a more complete read on how much work a player is doing to make the paint a difficult place to score.
Formula
Blocks = official blocked shots from play-by-play Contested_Blocks = shot contests at the rim where the player was tagged as primary defender but the ball was not fully blocked
Contested blocks are identified through the shot contest and defensive assignment tags in the play-by-play data. When a shot at the rim is contested — meaning a primary defender was identified at the point of the attempt — and the shot was not ruled a block, the defender receives a contested block credit. The distinction matters: a block is an outcome; a contested block is a defensive involvement tag.
Worked example
A center finishes a game with 3 official blocks. Looking at the play-by-play in more detail, he was also identified as the primary rim defender on 8 other shot attempts that were not blocked: 5 of those shots missed, and 3 converted over him. His contested block count for those 8 possessions is 8 — he was there and engaged, regardless of the outcome.
Total blocks: 3. Total contested blocks: 8. Combined rim presence across all these possessions: 11 events where he was the last line of defense. The blocks column captured 3 of them.
How to read it
Raw blocks vary a lot by position. Perimeter players rarely average more than 0.5 per game; elite shot-blocking bigs can reach 2.5-3.0 in a strong season. Contested blocks extend the range upward for active rim protectors who generate contests without always cleanly blocking the attempt.
| Combined blocks + contested blocks (per game) | What it typically signals |
|---|---|
| Less than 1.0 | Minimal rim involvement; mostly perimeter defense |
| 1.0 – 2.5 | Average interior presence for a big or switching forward |
| 2.5 – 4.0 | Active rim protector; generating real deterrence around the basket |
| More than 4.0 | Elite; among the most impactful interior defenders on any given night |
The ratio of blocks to contested blocks also matters. A player with many blocks but few contested blocks may be a gambler — going for the highlight when a close contest would have been the better defensive play. A player with high contested blocks and modest official blocks is doing the grunt work of rim presence without always getting the stat.
Limitations
Official blocks miss tipped shots that don't meet the threshold for a clean block call, and they sometimes miss weak-side swipes that altered the trajectory without fully deflecting the ball. At the margins, the official blocks number undercounts actual shot-altering events — a limitation that contested blocks partially addresses but can't fully solve without optical player-tracking data.
It's also worth noting that blocks and contested blocks don't capture shot quality allowed at the rim. A defender might show excellent block and contest numbers while still allowing high-percentage looks — the opposition may be beating the defense to the rim consistently and finishing efficiently despite the contest. Pairing these numbers with opponent field goal percentage at the rim gives a fuller picture of whether the rim protection is actually working.