Wednesday, March 17, 2010

The New MIT Putting Stat


A trio of stats guys at MIT have taken the Tour's data dump of Shot Link putting data and responded to the challenge of coming up with a "metric" that improves the Tour's "putts per GIR" and "total putts" per round metrics. Okay, so what do they come up with, on the banks of the Charles?

The new MIT "putts gained per round" stat has -- you guessed it -- lots and lots of impenetrable, CRAY-computer jamming calculations using mathematics symbols found only in graduate-level text books! Sigmas, other greek alphabet characters, Markov chains, derivatives, integrals .... Must be wonderful!!


But, alas, it's fundamentally just cleaner binocular lenses for watching paid ponies run 'round the track, instead of information that illuminates how the game is played well or poorly by golfers, pro or amateur.

The "metric" (fancy Latin word for comparison measurement, as in "mine's bigger than yours"), compares a specific pro's putting against the field average, with the wrinkle that putts are compared from the same distances. A pony-race comparison is already available, since the Tour compares / ranks pros in terms of who's first, second, ... last in putts per greens reached in regulation and also total putts per round, and also compares pros against the field average every event (the bar charts on each player's profile page). There are other percentage plus ranking metrics in the Tour "complete stats" page for every player, such as putts in the 0-3' range, "3-putt avoidance" (whatever that indicates), etc. The comparison of the pro against the field is available, too:

KEY STATS
Scoring Average (Actual)
68.73
70.68
Driving Distance
273.7
280.5
Driving Accuracy Percentage
75.61%
61.43%
Greens in Regulation Percentage
73.46%
66.79%
Scrambling
74.42%
59.86%
Putts Per Round
28.11
29.23
Steve Elkington Average
PGA TOUR Average

Above are the stats for the current #2 All-Around player in 2010, Steve Elkington. Here are the stats for the #1 All-Around stats leader Steve Stricker.
KEY STATS
Scoring Average (Actual)
68.31
70.68
Driving Distance
282.2
280.5
Driving Accuracy Percentage
68.42%
61.43%
Greens in Regulation Percentage
70.14%
66.79%
Scrambling
72.09%
59.86%
Putts Per Round
27.81
29.23
Steve Stricker Average
PGA TOUR Average

In putts per GIR, Stricker is today 1.713 and 17th, and Elk is 1.689 and 4th. In total putts, Stricker is 27.81 and 7th, and Elk is 28.11 and 17th. Is Elk a better putter than Stricker? It's not clear, but probably.

Does the tweaking of the Tour stats really help? Yes, it helps a tiny bit if you want to compare ponies on Tour, but nothing MIT or the Tour is doing is helping golfers understand putting better, or even modestly well.

The Tour has long known that neither "putts per GIR" or "total putts" is a precise comparison of pro A versus pro B. "Putts per GIR" improves "total putts" by looking only at the putting when both player's reach the green "in regulation", which means "not from close by the green as happens when a player nearly reaches the green on regulation and then chips on from nearby and faces a very close first putt". Arnold Palmer complained about Billy Casper defeating him in the US Open saying that of course he had fewer putts since he missed more greens than Palmer. Touche on "total putts" is a flawed comparison, but so is "putts per GIR", since pro A may stick his approach irons / wedges a lot closer than pro B and pro B may also be a short-knocker off the tee who only reaches any greens from much farther away than pro A and so is understandably facing first putts from "BFE" whereas pro A has quite a few "kick-in birdies".

The idea that Tiger Woods has a high "putts per GIR" ranking compared to, say, Bob Heintz, is a bit odd. In 2007 Woods ranked 4th in putting at 1.733 and Heintz ranked 13th at 1.749 putts every time he reached a green in regulation. However, Woods was 12th in driving at 302.4 yards and 1st in reaching GIRs whereas Heintz was 133rd in driving at 285.2 (17.2 yards shorter EVERY driving hole every round for a year) and was 146th on Tour in GIRs at 63.17% versus Tiger's ranking 1st at 71.2%. That year Woods ranked only 48th in total putts with 28.93 while Heintz ranked 16th with 28.59 (0.34 stroke better every round). Confusing, huh?

Okay, Heintz missed two or so greens more than Tiger every round (about 11 versus 13). So Tiger hits 2 greens and uses 3.466 putts, and Heintz misses these greens and uses 3.466 - 0.34 = 3.126 putts. So Heintz on these greens has a "putts per GIR" metric of 1.563 versus Tiger's 1.733? Naw ... But Heintz does make up 0.34 putts somewhere over 11 or so greens. Over 11 greens at 1.746 Heintz used 19.206 putts of his 28.59, so he used the other 9.384 on the remaining 7 missed greens. The "putts per missed GIR" metric is then 1.341. Tiger hits 13 greens and uses 1.733 putts each time for 22.529 putts of his total of 28.93. So Tiger's "putts per missed GIR" metric for 5 greens is then 6.401 / 5 = 1.280.

If you "weight" these two metrics ("putts per GIR" and "putts per missed GIR"), that means multiplying each by its ratio of the total greens. Then you get a "combined" stat for "putts per green" by adding the two weighted numbers. For Heintz, (1.746 x 11/18) + (1.341 x 7/18) = 1.585. You get the same answer if you simply divide the total putts for the round by 18 greens (missed plus hit GIRs). Tiger's combined metric is 1.607. So Tiger ranks below Heintz in putting this way.

So Heintz putts on GIRs from much farther away but does as well as Tiger, and has a couple of holes extra where he gets to chip close and then putt, ends up with fewer total putts than Tiger, looks worse in the stats than Tiger for putts per GIR, looks better than Tiger for total putts, and golfers aren't well informed as to what the difference might be. Is Heintz a better putter than Tiger? If yes, then why and how?

In 2002 Woods averaged drives of 293.4 yards (6th) and a GIR percentage of 74.% (1st) with Heintz at 284.2 (54th) for drives and 57% GIRs (202nd, last). That year Woods had a "putts per GIR" metric 1.766 (83rd) versus Heintz's of 1.682 (1st), and Woods was not only 10 yards longer each hole but more accurate off the tee as well. Was Woods really that far behind Heintz in putting skill? Despite his advantage in being much longer and more accurate?

Noah Liberman in his 2006 book The Flat Stick: The History, Romance and Heartbreak of the Putter, erroneously states that Brad Faxon has the best putting stat in golf history, 1.704 in 2000. Clearly, Liberman hasn't checked his history, as Heintz's stat is about 20% better in 2002 than Faxon's best ever, and 1.704 is a mark also attained by David Toms when he was ranked 2nd in 2002 behind Heintz. How does a "history" book about Tour putting miss the player who was 20% better than Faxon's and Tom's best? If Faxon was wearing an engineer's hat driving the locomotive of the Tour's "putting train" 100 cars long with 1.704 painted on the locomotive and Nick Faldo riding in the caboose with 1.805 (161st) on the side, how can Bob Heintz be all alone fully 22 cars further along the track than the entire Tour choo-choo?

So, yes, the Tour stats are primarily marketing the recognized pros by encouraging fans to get into the "race" among the players in contention on the weekend, watching the ponies circle the track for the roses. This leaves the explanation for WHY Heintz putts so very very well and WHETHER Tiger putts as well as the tv commentators proclaim rather confused for golfers trying to make sense of the game.

If the Tour wants to do more than get the fans into the pony race, and actually wanted to post stats that allow golfers to understand how pros meet the putting challenges they face and hence get a handle on what matters and how top players do well and other players do poorly, the Tour has had that capability for quite a while.

So what are the guys from Boston adding to this failure? Nothing other than a marginally sharper pair of trackside binoculars. Using the same distance putts to compute the mertic addresses the issue of "putts per GIR" not taking into account how close pro A sticks his approaches from far off, but still doesn't help golfers see why and how different pros do what they do or fail to do well. And basing the mertic on the sink / no-sink criterion leaves out of the picture HOW CLOSE or HOW POORLY the pro's effort turned out.

You can toss about all the standard deviations and Markov chains you want, the MIT "putts gained" metric is "pony watching" and not helping understand the WHYs and HOWs of putting. Okay, kudos for that investment of time and energy, guys. Now I can watch an event on tv with my laptop beside me and see that the Tour field usually misses from 15 feet, but Heath Slocum facing his 15-footer to survive the cut is less skillful on average than the field, so we'll see how it all works out this time. Great, he sinks his putt. Any clue why or how this outcome was different this time? Oh, right! They don't show Heath Slocum on Friday lunchtime putting to make the cut.

According to MIT, the new "putts gained" stat ranks Tiger in 2009 as 2nd (gaining 0.858 stroke per round with his putter on the field) whereas Heintz ranks 13th (gaining only 0.559 stroke per round with his putting). Presumably, this indicates that if Tiger and Heintz faced 28-30 putts all the same length (whatever is the Tour field average for total footage faced in a round divided by 18 greens), then Tiger would best Heintz by 0.299 stroke, on average each round all year. What in the world does that tell me about how either player gets the putter working? Even more basically, how would I compare my own lame efforts on the greens at the muni to try to get inspired to do as well? I certainly can't compute this stat myself in the margins of the score card! And what does 17th ranking mean unless you know the top, the bottom, and the "mean" in between?

Academics COULD help a lot, but this particular effort isn't very helpful. Usually, academic "science" contributions to golf in general are "flat, unfizzy" draughts, mostly because the hubris of the educated elite leads Ph.D. sorts to assume they know the demands and conditions of the sport, or assume that a little brushing up on the sport in a book or article or two suffices to get started with the "serious" work. This is the case with the MIT folks, as they "assume" different courses and greens make much difference over a year. They state that some players putt on much more difficult greens than others. Well, okay, Oakmont is different, Augusta National is faster than usual, and a couple of greens are bumpier due to poa and the like. But the typical pro plays 25 events of more. About 20 of those greens are very same-y, Stimp 11 and true and smooth, double cut, desiccated, and pack and rolled. The faster more sloped and contoured greens like Augusta National are not played by all pros, so just eliminate that from the metric. Or make an Augusta-only metric. The MIT choice is to give the Masters players a little boost by excusing them if they don't putt so well as middle-of-the-pack pros at Reno.

So what SHOULD the Tour do? How about recording not simply the distance from the hole but also the direction of the fall line thru the hole, the slope near the hole, and the ball's position relative to the fall line? That will indicate the break and the uphill-downhill situation and the distance and whether the putt misses high or low, long or short, and by how far. How would that be done? Simply use Ron Wilkerson's Exelys Digital slope/ fall-line reader each round 18 times once the pins are set. Then laser the pins, each ball position, and the angle of the ball-hole line off the fall line. Or digitize the perimiter of the green and indicate ball position with a pointer -- close enough for government work and much more indicative of the problems the golfer faces each separate putt: break, slope steepness, distance, uphill-downhill, green speed, and so forth.

A few "lone ranger" golf enthusiasts acting without salary or publicity have made substantial efforts to track meaningful putting stats that help golfers understand this part of the game for over four decades now. Cochran and Stobbs back in 1968's Search for the Perfect Swing, Clyne Solely's 1979 How Well Should You Putt, HA Templeton's 1984 Vector Putting: The Art and Science of Reading Greens and Computing Break, and Werner and Grieg's 2000 How Golf Clubs Really Work (with 75 pages of science on putting with stats for pros and amateurs alike) come to mind immediately. A Golf Digest article back in the 1970s compared pros using total footage of putts faced divided by total putts, and by this metric Arnold Palmer came out way ahead, dropping a couple long ones almost every round while hitting greens.

Want to see better than the Tour confusion or MIT "tweak" for tracking stats on the green in a meaningful way for BOTH comparing ponies on the track and for understanding how pros handle what they face? Sure you do. We'll have to wait, though.

Cheers!

Geoff Mangum
Putting Coach and Theorist

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Optimal Putting: Brain Science, Instincts, and the Four Skills of Putting (2008, 282-pages) -- only $9.95.

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