Tuesday, February 14, 2012

How Good is "Strokes Gained - Putting?"

For those that need a refresher, Strokes Gained - Putting is the Tour's new putting statistic. It compares the distance of each putting opportunity to a model of the average Tour performance from that distance to calculate strokes gained or lost.  Each player's totals for each round is compared to the average of the field to reveal his strokes gained or lost.  It works!

It was great to see Phil and Tiger paired together in the final round of the AT&T Pebble Beach National Pro-Am, at least for a few holes...  I cannot recall two more contrasting performances by marquee players.  Phil beat Tiger head to head by 11 strokes AND in the final round while both had their sights set on a win.  But wait, even more astounding was that ten of the eleven strokes was PUTTING alone.

How do I know this?  Their respective Strokes Gained - Putting numbers for the final round are:
    Phil:  4.799  (Phil beat the field average by almost 5 strokes.)
  Tiger: -5.288  (Tiger was 5+ strokes worse than the average performance of the field.  His ShotByShot.com Putting Handicap for the round was 21.  This is as high as I've seen for a tour player - much less one in contention to win the tournament.)
Put the two together, and Phil beat Tiger, on the greens alone, by 10 strokes!

I am a big fan of the Tour's new putting stat.  As I have trumpeted to anyone that will listen, I adopted this method of putting analysis 20 years ago and it has been the basis for ShotByShot.com's putting analysis since I launched the website in 2005.  That said, given the vast differences in the two player's long and short games, how could these game components (everything BUT putting) account for only 1 stroke?  See if you can follow my math.

First, the Putting
Tiger took 31 putts to Phil's 26 = 5 strokes.  If they had putted from the same spots (distances) on all 18 greens, these FIVE strokes would have been the extent of the difference in their putting performance, but they did not.

Tiger's average putting distance was 6 feet closer than Phil's (14 vs. 20 feet).  The Tour's model allocates another five strokes to their respective distances over the 18 holes.  It is not as simple as the difference in the averages (14 vs. 20 ft.) because the Tour's model, like mine, is not a straight line.  The five strokes are an accumulation of the differences in the values of each specific distance.  Please accept my word on this.

The Rest of the Game = 1 Stroke??
Bottom line, Tiger hit five fewer GIR's than Phil (9 vs. 14) with the same number of full swings (34).  With fewer GIR's, Tiger needed six more short game shots (10 vs. 4) to reach his 18 greens.  Subtract five because Tiger's ultimate putting positions were five strokes better/closer than Phil's, and there's the single stroke needed to make the total strokes add up.

Allocating the strokes lost or saved between Tiger's and Phil's long and short games tells another story, but for another time.  Please contact me with questions @ PSanders@shotbyshot.com.