Will new statistics unlock the secrets of golf?
The foundation of shot value is the idea that, once you have a huge database of golf shots, it's possible to set a benchmark for performance from every position on the course. Broadie uses the scratch golfer (someone who shoots par) as his benchmark. Using the data he collected, he determined how many strokes it would take a scratch golfer, on average, to get the ball in the hole from every inch of turf—everywhere from the first tee to the bunker that guards the 18th green.
Imagine that you are standing in the fairway with a 150-foot approach shot to the green. You look down, and instead of a yardage marker, you see a stake with the number 2.5. That's the average number of strokes it takes a scratch golfer to hole out from that spot. Picture these same sorts of markers everywhere. The tee box on a difficult par 4 may say 4.6. A 60-yard sand shot may have a 2.7 marker, and so on.
Once you have a benchmark "fractional par" value for every point on a course, you can figure out the value of every single shot. In a paper presented at the World Scientific Congress of Golf (PDF), Broadie gives the example of a 140-yard par 3 that plays, for the scratch golfer, like a par 3.2. Let's say a golfer hits his tee shot to within 14 feet, moving from a location where it takes an average of 3.2 strokes to hole out to a spot where it takes an average of 1.8 strokes to finish. The simple arithmetic to determine the value of the shot: 3.2 - 1.8 - 1 (for the stroke that was taken) = 0.4. The superb approach shot has given our fictional golfer a four-tenths of a stroke advantage over a scratch golfer.
Like all revolutionary concepts, shot value takes a few moments to get your head around. Perhaps the easiest place to grasp it is the green. Let's return to that 14-foot putt for birdie on the par 3. According to Broadie's research, a scratch golfer makes 14 footers about 20 percent of the time, gets home in two about 80 percent of the time, and rarely three putts. That gives the 14-foot putt a fractional par of 1.8—if you sink the putt, you pick up eight-tenths of a shot. If you just miss it, you lose two-tenths of a stroke.
While we write down our golf scores in whole numbers, Broadie's concept of shot value reinforces that a golfer loses or gains fractional advantages on every swing. This aligns with what it's like to be on an actual golf course. Every hole has certain places where it's great to land your ball—a spot where there's a good angle to the green, or an easy uphill putt—and other spots where you're "in jail," or out of bounds, or blocked by a tree. Hitting a shot to a good position is obviously more valuable than hitting it to a bad position. What shot value does is tell you exactly how much more valuable.
The beauty of shot value is that you can add it up. How many strokes is a golfer gaining or losing due to his approach shots? How about his putting? It's simply a matter of tallying individual shot values and comparing the results to the player's peers'.
In order to see shot value in action, Broadie analyzed for me how Tiger Woods won the 2008 Arnold Palmer Invitational at the Bay Hill Club. Tiger was at the height of his powers during this tournament—a golfing superhero who looked nothing like the all-too-mortal duffer who finished a breath out of last place at Firestone last week. The victorywas capped by this famous highlight:
Tiger is standing over a 24-foot putt for birdie. If he misses, he will enter a playoff against Bart Bryant. If he makes it, he will win his fifth consecutive tournament and tie Ben Hogan on the all-time wins list. As Tiger reads the break, the announcers unleash a series of statistical insights. "Probably means nothing right now, but he is 0 for 21 this week on putts over 20 feet," says color analyst Johnny Miller.
Tiger strokes the putt. The ball slides toward the hole … rolling, rolling … it's in! Tiger throws his hat onto the turf, then does a double fist pump. "Hello, Ben Hogan!" shouts play-by-play man Dan Hicks. Bart Bryant shakes his head in the scorer's booth. The crowd walks to the clubhouse, marveling at another example of Tiger's greatness in the clutch—he'd saved his best putt of the week for the 72nd hole.
Photograph of ShotLink volunteer by Sam Greenwood/Getty Images. Video of Anthony Kim at the AT&T National © 2009 CBS. All rights reserved. Video of Tiger Woods at the Arnold Palmer Invitational © 2008 NBC. All rights reserved. Putting equation and chart from "How To Catch a Tiger: Understand Putting Perfomance on the PGA Tour," by Douglas Fearing, Jason Acimovic, and Stephen Graves.