Leverage on PBP Stats refers to the analysis of basketball play-by-play data to determine how crucial a possession is to the outcome of the game. Leverage is calculated based on a model that considers factors like the score margin, time remaining, and win probability to assign a value to each possession. This helps analyze a player's or team's performance in different game situations, differentiating between high-leverage (close and late) situations and low-leverage ("garbage time") situations.
What PBP stats leverage is
A measure of game situation: Leverage quantifies the importance of a possession, with higher values indicating a greater impact on the game's outcome.
Based on a win probability model: It uses a model that takes into account the current score, time left, and the pre-game win probability for each team to determine the leverage of a possession.
Used to identify meaningful performance: It allows for the analysis of how players perform in meaningful parts of the game versus "garbage time".
How it's calculated
The model uses a possession's specific context (score, time remaining) to calculate a "leverage value".
This is done by first determining the possible outcomes of a possession (e.g., scoring \(0,1,2,\) or \(3\) points) and their respective win probabilities.
A weighted average is then calculated based on the frequency of these outcomes and their change in win probability, resulting in a single leverage value for that possession.
Examples of its use
Player performance: It can be used to see if a player is scoring primarily in low-leverage situations or if they are performing well when it matters most, as shown in the analysis of LeBron James' points in high-leverage situations compared to other prolific scorers.
Team analysis: It can provide a summary of team performance by classifying possessions into categories like "high," "medium," and "low" leverage to understand how a team performs overall in different scenarios.
Game analysis: It can be used to analyze trends in the NBA, such as the percentage of close games or comeback victories in a given season.