Strokes Gained: Putting is based on comparison of the number of putts taken by an individual player from a specific distance versus a statistical database of that same information obtained for all PGA TOUR players.

Strokes Gained: Putting was initially developed for use by TOUR players, but its usefulness as a measure of putting performance for a typical golfer can be seen in the following scenario. After missing the green on hole 1, the golfer then chipped to 8 feet from the cup; his approach shot on hole 2 hit the green, but it finished 22 feet from the pin. He subsequently needed two putts to finish the hole in each case. There would be no difference in our typical golfer’s putting performance for the two holes when evaluated simply by counting the number of putts (2) required for each. However, as detailed below, an analysis by Strokes Gained: Putting reveals a different result.

Using putting data collected via ShotLink for TOUR players, the average number of strokes needed from 8 feet is about 1.50 … that is, those golfers make about 50% of their putts from that distance: (0.50 x 2) + (0.50 x 1) = 1.50 . Thus, if a player takes just 1 stroke to sink an 8-foot putt, Strokes Gained: Putting is (1.50 - 1) = +0.50 ; the golfer gained one-half stroke putting on that hole. On the other hand, if 2 putts are required to finish from 8 feet, Strokes Gained: Putting for that hole is (1.50 - 2) = - 0.50 ; therefore, the player lost one-half stroke on the hole. In contrast, from 22 feet TOUR players require 1.90 strokes on average to finish (the equivalent of making about 10% of such putts). Thus, sinking a 22-foot putt yields a Strokes Gained: Putting value of (1.90 – 1) = +0.90 , while two-putting from that distance produces a figure of (1.90 - 2) = -0.10 .

When the above Strokes Gained: Putting values are used to evaluate our typical golfer’s putting results (hole 2: 22-feet = -0.10 vs. hole 1: 8-feet = -0.50), it becomes apparent that his performance was actually 0.40 strokes better on hole 2 than on hole 1 (-0.10 – (-0.50) = +0.40) despite needing 2 putts on each hole. Because Strokes Gained: Putting normalizes for first putt distance, it allows a more accurate comparison of putting performance than simply counting total putts needed. Furthermore, Strokes Gained: Putting is cumulative, so total Strokes Gained: Putting for a round is simply the sum of Strokes Gained: Putting for all holes and can be used for accurate round-to-round putting performance comparisons. Total Strokes Gained: Putting also can be averaged by summing the values from multiple rounds and dividing by number of rounds played.

The concept of Strokes Gained: Putting, developed by Professor Mark Broadie of the Columbia University Business School and later refined by the PGA TOUR, is a by-product of the TOUR’s ShotLink Academic program.

I’ve heard people say putting is 50 percent technique and 50 percent mental.
I really believe it is 50 percent technique and 90 percent positive thinking, see,
but that adds up to 140 percent, which is why nobody is 100 percent sure
how to putt.
— Chi Chi Rodriguez, Hall of Fame Golfer