PACIFIC PALISADES, Calif. – Dustin Johnson is your first-round leader of the Northern Trust Open after shooting a 66. His round also served as a great example of why strokes-gained putting has become accepted as the best indicator of putting performance.
On Thursday, Johnson took 30 putts, which ranked T-109 among the field. Sounds like a bad day at the office with the short stick, right? As ESPN’s Lee Corso would say, not so fast my friends.
Several years ago, the Tour recognized that its measurements of putting – putts per round, putts per green in regulation, and total distance putts made – were flawed. Fewer putts per round, for instance, may be an indication of good putting, but it could just as easily be a reflection of good chipping or poor iron play. In Johnson’s case, his 30 putts had a lot to do with hitting 16 of 18 greens in regulation, which tied for the best in the field with Charley Hoffman.
Johnson gained 2.267 strokes on the field once his ball landed on the green, which ranked 13th in the first round. How is that figure calculated? Quite simply, putts gained measures the number of putts better or worse than the field from a given distance. It is the first putting stat that valued distance. The formula is simpler than E=MC2. In fact, its creator Mark Broadie, who teaches at the Graduate School of Business at Columbia University, says you don’t need to be a rocket scientist to understand it.
Putts gained = PGA Tour average putts to holeout – Actual putts to holeout
The Tour average putting benchmark is computed in one-inch increments each year using the nearly half-million putts in the ShotLink database from the prior year on tour, Broadie said. For example, suppose a golfer lands on the green 33 feet from the hole and then sinks the putt. For tour golfers, the average number of putts to holeout from 33 feet is 2.0, so the one-putt represents a gain of one stroke (2.0 average putts – 1.0 actual putt). A two-putt from 33 corresponds to zero putts gained, and a three-putt to a loss of one stroke (2.0 average putts minus 3 actual putts). In most cases, the putts gained or lost on a hole will be a fraction of a stroke.
“This is arithmetic,” Broadie said. “If you can subtract two numbers that’s all you need.”
Interestingly, Johnson’s first round also displayed the flaws in another Tour statistical category. The Tour measures driving distance for the field at two holes. At Riviera, that would be the 11th and 12th holes, where Johnson averaged a skimpy (for him) 282.9 yards, or 88th longest in the field. However, on the 13th hole, Johnson ripped a drive that traveled 349 yards, or the longest of the day.