Here’s a quick rundown of the methodology behind the Strokes Gained-Putting metric developed by Columbia Business School Professor Mark Broadie.
First, the PGA TOUR calculates the average number of putts a player takes to reach the hole from every distance, using ShotLink data from the previous year. That’s called the “putting benchmark.”
During a tournament, the number of putts a player takes is subtracted from that average value to determine strokes gained or lost. Say a player’s putting benchmark from seven feet, 10 inches is 1.5 putts. If a player one-putts from the distance, he gains 0.5 strokes. If he two-putts, he loses 0.5 strokes. And if he three-putts, he loses 1.5 strokes.
There is one further adjustment made at the end of each round. Strokes Gained-Putting quantifies a golfer’s putting relative to the field, taking into account the initial distance of each putt. Suppose a golfer gained a total of 2.7 putts against his putting benchmark for a round. But the greens on this particular day might have been easier to putt than normal, and the entire field gained an average of 0.4 putts relative to their putting benchmarks. As a result, that one golfer gained 2.3 putts relative to the field for that round.