Strokes Gained: In 2019, the Key to Scoring is an Iron Will

Again this season, Strokes Gained Approaching The Green showed the strongest correlation to a player’s score.

What makes for a good golfer on Tour? Stats, Strokes Gained, Skill, or maybe bombing the ball?

What’s the most important skill for a top-flight PGA Tour pro? Is it driving the ball a long-distance? Sports Illustrated suggested as much just this past spring. SI’s Daniel Rapaport published a lengthy and thoughtful analysis in February arguing that increased driving distance is changing the game in fundamental ways.

Or, as the cliché goes, is it putting? The adage “Drive for show, putt for dough” is generally ascribed to the great 1940s South African, Bobby Locke, but it has been accepted as wisdom ever since.

Statistically, it turns out that the correct answer is “none of the above.” In 2019, as has been the case since Strokes Gained Data was first collected 15 years ago, the ability to stroke an iron within a one-putt distance of the flagstick emerges as the pre-eminent trait among the most successful pros.

The evidence lies in the correlation between the four major Strokes Gained categories and scoring average. Among the 188 tour pros who played enough rounds to provide a basis for statistical measurement, there was a 61.8 percent correlation between a player’s rating in Strokes Gained Approaching The Green and his stroke average.

That’s on a scale where 0 percent indicates no relationship whatsoever and 100 percent represents a total relationship.

Since Strokes Gained data was first collected in 2004, the correlation between Strokes Gained Approaching The Green and stroke average has always been the strongest of the four Strokes Gained measurements.

That 61.8 correlation is down from one season ago (69.1), but that decline reflects a general ebbing of the correlation between skills and scoring average in 2019.

The correlation between Strokes Gained Off The Tee and scoring average was 50.8 in 2019. That’s off about 10 percentage points from the 60 percent correlation between those two measurements in 2018.

The correlation between Strokes Gained Around The Green and scoring average was 40.5, off about seven percentage points from the 47.6 percent correlation of one season ago.

The only correlation that strengthened during the 2019 season – compared with 2018 – involved putting. That correlation was 40.4 percent during the 2019 season, about 10 percentage points higher than the 30.5 percent correlation in 2018.

Historically, putting has generally contained the weakest relationship to scoring average. Its correlation has been the weakest in each of the past four seasons.

Here’s a table showing the change in the four major correlation categories for each of the past five seasons.

• Year       SG Tee                  SG App.                   SG Ard.                   SG Putt
• 2015       51.5                        64.3                        31.4                        41.9
• 2016       55.7                        70.7                        32.8                        24.2
• 2017       62.7                        72.4                        32.1                        25.1
• 2018       60.0                        69.1                        47.6                        30.5
• 2019       50.8                        61.8                        40.5                        40.4

What do all those numbers mean? On a tournament-to-tournament basis in 2019, the best putters have tended to win. But over the course of a full season, putting skill is at best only a moderate indicator of success. That was true in 2019, as it has been true consistently on tour.

The game’s long drivers have a clearer advantage…but not the predominant one many believe. Rather, the data shows it’s the ability to stick an iron that consistently reduces a player’s scoring average.

The other interesting aspect of the data lies in the overall relationship of the correlations to the stroke average. Historically, that correlation has averaged about 48 percent, although it has varied from season to season.

In 2018, the average correlation exceeded 50 percent for the first time since 2012.  This season it receded to more historically normal levels, averaging about 48.3 percent. Rough translation: Following a brief flurry into the realm of more technocratic approaches to the game in 2018, players this year were a bit less mechanical, a bit more artistic as a group.

Historically, the strongest relationship between Strokes Gained and scoring average occurred in the first year the data was collected, 2004.  Led by a 78.6 percent correlation in Strokes Gained Approaching The Green, the average that year was 52.9 percent. The weakest correlation was 44.75 percent in 2008.