Beyond FG%: Understanding Shot Quality
Field goal percentage is one of the most misleading stats in basketball. A center who dunks at 65% FG% isn't more skilled than a wing who shoots contested threes at 40%. Shot Quality Analysis goes deeper by measuring the expected value and difficulty of every shot a player takes.
Our Expected Points Per Shot (PPS) metric assigns point values based on where players shoot from and how efficiently they convert. A three-pointer made at 38% is worth more per attempt (1.14 points) than a two-pointer made at 50% (1.00 points). This simple math explains why the NBA has shifted so dramatically toward three-point shooting.
The Scatter Plot Explained
The scatter plot maps Shot Difficulty (x-axis) against Expected PPS (y-axis). Players in the top-right quadrant are the most impressive — they take hard shots AND make them efficiently. The top-left quadrant shows efficient players who take easy shots (rim-runners, catch-and-shoot players). The bottom-right shows players taking too many difficult shots without the efficiency to justify it.
Shot Difficulty Metric
Shot Difficulty estimates how challenging a player's typical shot selection is, factoring in their three-point attempt rate, volume relative to minutes played, and the inverse of their field goal percentage (lower FG% at high volume suggests tougher shot selection). A player taking lots of threes off the dribble has higher difficulty than one taking open catch-and-shoot threes.
Frequently Asked Questions
What is Expected Points Per Shot?
Expected PPS measures the average point value of each field goal attempt, accounting for the mix of two-point and three-point shots and their respective conversion rates. A higher PPS means more efficient shot selection.
Why is FG% misleading?
FG% treats all makes equally. A player shooting 60% on layups isn't necessarily more valuable than one shooting 40% on threes, because 3PT attempts at 40% generate 1.2 points per shot vs 1.2 for 2PT at 60%. Shot quality metrics capture this distinction.
What does the Shot Quality Index combine?
The SQ Index combines Expected PPS, field goal efficiency relative to league average, three-point efficiency, and a bonus for maintaining efficiency at high difficulty levels. It answers: who takes AND makes the hardest shots?
Who typically has the highest shot quality?
Players who combine elite efficiency with volume scoring and three-point shooting tend to top the list. Think efficient wings and guards who can score from all three levels at above-average rates.
How is shot difficulty calculated?
Shot Difficulty factors in three-point attempt rate (more threes = harder), scoring volume per minute (more points in less time = harder), and the inverse of FG% (lower percentage at high volume suggests tougher shots).