fourfactor

The Four Factors is a framework in basketball analytics identifying four key determinants of a team’s success: effective field goal percentage, turnover percentage, offensive rebound percentage, and free throw rate. Introduced by Dean Oliver in his book Basketball on Paper, the concept is used to assess both offensive efficiency and defensive strength, often on a per-possession basis to normalize for pace. The four factors have become a standard reference in coaching analytics, scouting, and game analysis.

Effective field goal percentage (eFG%) accounts for the value of 3-point shots and is calculated as eFG% = (FG + 0.5 × 3P) / FGA. Turnover percentage (TO%) measures how frequently a team loses possessions, typically computed as Turnovers / Possessions. Offensive rebound percentage (OREB%) reflects success at securing additional chances, commonly defined as ORB / (ORB + OppDRB). Free throw rate (FTR) tracks how often a team scores from or gets to the line, often expressed as FTA / FGA (or FT Rate = FTA / FGA).

Together, these factors are used to explain a large portion of a team’s scoring margin and winning percentage. They emphasize shot quality, ball control, extra possession opportunities, and opportunities from free throws, providing a per-possession lens that helps compare teams across different playing styles and paces.

Limitations include the model’s simplifications, such as not fully capturing defensive complexity, pace nuances, or player-specific factors. Despite this, the Four Factors remain a foundational concept in basketball analytics, guiding analysis, strategy, and interpretation of team performance.