NBA.com matchup tracking + play-by-play · 2020-21 to now
Toughest Defenders
Who takes the hardest assignments, how scorers fare against them, and how much they lower what their team allows. Hover any column for a definition; the full method is on the Methodology page.
What this can't seeHelp defense, contest quality, schemes and noise all limit matchup data. Click to read before leaning on any single number.
- Help defense lands on the helper. NBA.com credits a shot to whoever is guarding the shooter when he shoots. If a guard gets beat and the center rotates over, the shot counts against the center. That's why raw points allowed isn't used here, and why Team Defense Impact carries a third of the index.
- No contest quality. These totals don't record how close the defender was or how good the shot was. A tight contest on a tough make counts the same as an open one. Contest quality is a separate research project.
- Switches and schemes blur assignments. Matchups are split by time on the floor, so switching teams spread credit around and drop coverages put bigs on a lot of drives. Role and scheme still shape these numbers after comparing within position.
- Assignment difficulty isn't defense by itself. Guarding stars is a coach's vote of confidence, not proof of stopping them. It's one third of the index, alongside results and Team Defense Impact.
- Noise. Single seasons are noisy. Team Defense Impact starts each season from the player's prior estimate and last season's D-HPM, which steadies it (it repeats year to year at about r = 0.8), but a breakout or a decline shows up gradually. Last 3 seasons is the most reliable view; the live season is a first look.
- Coverage and overlap. NBA.com's matchup tracking covers about 97% of shots; off-ball work that never leads to a shot or turnover isn't counted. Forced turnovers appear in Results and steals in Team Defense Impact's starting point, so turnovers count slightly twice.
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Leaderboard
Who they guard vs what they take away
Across: assignment difficulty. Up: Team Defense Impact. Color: Index, pale to deep gold. Size: matchup possessions.
Top right: takes the hardest jobs and his team defends better with him on the floor.
Click any dot to open that player's breakdown.