NBA rule change increased end-of-quarter heave rate from 58% to 94%
9 reported
A recent study by James W. Kemper and Noah Liptack examined how performance metrics can misalign individual and organizational incentives, using the NBA as a case study. The researchers analyzed play-by-play data from the 2015-16 through 2025-26 seasons, focusing on the 2025-26 Heave Rule, which removed the individual statistical penalty for end-of-quarter heaves. Before the reform, players heaved on 58 percent of opportunities, with reluctance concentrated among efficient shooters and players in contract years. After the reform, the heave rate jumped to 94 percent, and the efficiency gradient collapsed. Difference-in-differences estimates using the untreated fourth quarter confirmed the effect was sharp, immediate, and smallest among players with the least efficiency to protect. The study concluded that removing a metric distortion realigned individual behavior with team objectives almost completely.
What’s reported
The study modeled an NBA player’s decision to attempt a low-probability “heave” as a metric-driven principal-agent problem.
Data covered the 2015-16 through 2025-26 seasons.
The 2025-26 Heave Rule removed the individual statistical penalty for end-of-quarter heaves.
Before the reform, players heaved on 58 percent of opportunities.
Reluctance to heave was concentrated among efficient shooters and players in contract years.
After the reform, the heave rate jumped to 94 percent.
The efficiency gradient collapsed after the reform.
Difference-in-differences estimates using the untreated fourth quarter confirmed the effect was sharp and immediate.
The effect was smallest among players with the least efficiency to protect.
Key figures
James W. Kemper (researcher)
Noah Liptack (researcher)
Kevin Lewis (credited with bringing the paper to attention)
Sources: marginalrevolution.com
