The Four Factors
The four ways a team wins or loses possessions
The Four Factors — Effective Field Goal Percentage, Turnover Rate, Offensive Rebounding Rate, and Free Throw Rate — describe the four possession-level dimensions that determine basketball efficiency. Originally identified by basketball statistician Dean Oliver, they remain the most useful framework for understanding why teams win or lose without reducing everything to a single number. Macfax computes both raw and opponent-adjusted versions of each factor.
What It Measures
Four rate statistics, each with an offensive and defensive version. eFG% measures shooting quality, with three-pointers weighted appropriately for their extra scoring value. TOV% measures ball security as turnovers per possession. ORB% measures second-chance creation as a share of available offensive rebounds. FTR measures free throw generation relative to field goal attempts. Margins compare the offensive and defensive versions of each — positive margin always means your team has the structural edge on that dimension.
Why It Matters
Raw box-score stats reward pace and ignore context. A team that plays fast generates more raw points and rebounds — that does not mean they are better per possession. The Four Factors strip pace out and isolate how a team wins possessions, which is more actionable than a single efficiency number. Two teams can have the same AdjEM through completely different profiles — one through elite shooting, one through elite defense and rebounding. The Four Factors make that difference visible and comparable.
How to Interpret
Look at margins first. A team with eFG% 54% is good; that same team holding opponents to 46% eFG% has an +8 eFG Margin, which is excellent. The margin direction is consistent: positive is always advantageous. eFG Margin = your eFG% minus opponent eFG%. Turnover Edge = opponent TOV% minus your TOV% (reversed so positive means you protect the ball and force turnovers). Rebounding Edge = your ORB% minus opponent ORB%. FTR Margin = your FTR minus opponent FTR.
Formula
eFG% = (FGM + 0.5 × 3PM) / FGA TOV% = TOV / Possessions ORB% = OREB / (OREB + Opp DREB) FTR = FTA / FGA eFG Margin = Team eFG% − Opp eFG% Turnover Edge = Opp TOV% − Team TOV% Rebounding Edge = Team ORB% − Opp ORB% FTR Margin = Team FTR − Opp FTR
Technical Notes
- eFG% weights three-pointers at 1.5× because a made three scores 50% more than a made two, making it a fair per-shot comparison across different shot selection profiles.
- Possessions are estimated using the standard formula: FGA − OREB + TOV + 0.475 × FTA. The 0.475 multiplier accounts for and-one plays and technical fouls where free throws do not end a possession.
- Macfax displays adjusted Four Factors by default. Each game-level factor is normalized against the opponent's capability on that specific dimension and to a neutral-site baseline. Exact calibration is consistent with the adjusted efficiency rating methodology.
- Turnover Edge is intentionally inverted from raw TOV% so that positive values are uniformly favorable across all four margins.
- Raw (unadjusted) versions of all Four Factors are also available for reference.
- •eFG% does not distinguish shot quality within make type — a corner three and a mid-range two count the same if both go in.
- •FTR does not separate intentional end-of-game fouling, technical fouls, or clear-path fouls from genuine offensive free throw generation.
- •Offensive rebounding rates can reflect team philosophy as much as capability — teams that emphasize transition defense may intentionally sacrifice offensive boards.
- •Adjusted Four Factors stabilize more slowly than adjusted efficiency for teams early in the season.
- •Box-score data captures outcomes but not decision quality — a team can have a high ORB% while taking poor shots that create more rebound opportunities.
Illustrative example: Team A posts an adjusted eFG Margin of +7.8, Turnover Edge of +6.3, Rebounding Edge of +5.3, and FTR Margin of +9.5 — positive on all four. This is an unusual and highly favorable Four Factor profile that typically correlates with elite adjusted efficiency margin. In practice, most strong teams dominate one or two factors and are average or slightly negative on the others. A team with +8 eFG Margin but −3 Rebounding Edge is still very dangerous — they just win differently.