How a mathematician and sports analytics expert transformed the game of golf.
In the world of golf, Mark Broadie is an unlikely celebrity. He is not a professional athlete. Professor Broadie is a mathematician and expert in sports analytics who designed what’s known as the strokes gained method, a way of measuring a golfer’s performance that has transformed the world of sports statistics and, in many cases, the game itself.
Detailed in his 2014 book, Every Shot Counts, strokes gained uses historical data to compare a golfer’s rounds to those of other players based on the start and end point of each player’s shot. The measurement represents a great equalizer; before it was adopted by the PGA Tour in 2011, golf statistics couldn’t differentiate between a player who sank a putt from 3 feet away, and one who made it from 20 feet. This allows players to assess their strengths and weaknesses relative to their opponents’, and provides greater context for fans and analysts to each golfer’s game.
“It’s become part of the lingua franca of the sport,” explains Ken Lovell, senior vice president of ShotLink Business Operations and Golf Technology for the PGA Tour.
A New Jersey native, Broadie began golfing as a teenager, and played sporadically following a move to New York City in the 1980s. After joining an area golf club in the early 1990s, he played more frequently and began to think about how to combine his passion for the game with his data-driven academic pursuits.
In the last decade, Broadie’s system has done for golf what the development of sabermetrics has done for baseball—offered new ways to analyze and interpret an old game. Hardly a tournament broadcast goes by without a commentator mentioning the stat, and earlier this year, the Golf Channel called the creation of strokes gained one of the top 25 most impactful moments of the last 25 years.
Broadie says that since developing strokes gained, golf stars such as Rory McIlroy, Luke Donald, and Justin Thomas have reached out to him about how they base their practice sessions on knowing what their strokes gained number is on a certain course.
“I’ve heard some very nice quotes from players and coaches that they use strokes gained all of the time,” he says.
As it’s relatively easy to socially distance while playing a round, both the professional game and the golf industry have seen gains in popularity since the onset of the pandemic. Lovell notes that television ratings for the PGA Tour have been up since tournaments resumed on June 11, and that there has been an uptick in golf equipment sales.
He adds that statistics such as strokes gained enhance the experience of the game for fans.
“They are a way to show and to entertain people at a deeper level than just putting a picture in front of them,” Lovell says.
What is the story behind the creation of strokes gained?
I wanted to combine my personal interest in golf with my professional interest in analytics.
I realized that the analytics work I was doing at Columbia Business School would have ideas that could answer what I thought would be interesting questions in golf. One of them would be explaining where the difference comes from, between a golfer whose average score is 90, versus a golfer who typically shoots 80. Where did those 10 strokes come from?
To answer that question, you need shots. I looked around to see if I could get shot-level data looking at how far a golfer whose average score is 90 hits the ball compared to how far an 80 golfer hits the ball, plus see how many times they landed in the fairway. There wasn’t any information on that. So, I created a program to gather shot-level data for amateurs.
In the 80 versus 90 golfer example: If you figure out how good and how poor each shot is relative to a benchmark, the value of all shots will add up to the 10-stroke difference over the round. Then you can see how much putting, driving, and other parts of the game contributed to that 10-stroke difference.
How did the PGA Tour become involved?
In 2003, around the same time I was assembling my data, the PGA Tour started collecting shot-level data for professionals, but they would not give it to me. They said, “It’s too expensive, we’re just not going to give it way for free.” The tour used laser technology to track where every shot starts and where every shot finishes. Then in 2008, they wanted to improve their putting stats. They came to me and said, “You’ve been doing this stuff with strokes gained, can we adapt this for use on the PGA Tour?” So they agreed to share their data.
There’s a lot of luck involved in these things. You can have a great idea and there’s no data. You can also have the data and an idea, but nobody is interested in it. I had a method that I had developed and the PGA Tour had a need.
Did you always feel that golf statistics needed to be updated?
The statistics that were in use in the early 2000s were the same ones that were in use in the 1950s. If you go back to pre-computer days, you can count things: How many putts? How many fairways did you hit? How many greens did you hit? With the collection of shot tracking data the PGA Tour created hundreds of new stats, but it was too much information and too little insight. They presented all of this stuff that people couldn’t make heads or tails of. So initially, they didn’t want strokes gained to be the 351st stat that was just lost in the shuffle.