In 2019, the Golf Channel called Professor Mark Broadie's method of measuring a golfer's performance one of the 25 most impactful moments in the sport in the past 25 years.
The strokes gained method, developed by Broadie and detailed in his book, Every Shot Counts, lets golfers use historical data to compare their rounds to others' based on the start and finish locations of each player's shot on the golf course.
Broadie, the Carson Family Professor of Business, explained how strokes gained could impact the business world and how data and analytics will continue to change the way we think about and enjoy sports.
How does your research on strokes gained translate to the business world?
It puts data in a context that makes performance measurement managerially relevant. There's certainly a ton of examples in sports where player performance, team performance, and individual plays are measured relative to an appropriate benchmark. The idea of strokes gained is to measure the quality of a shot relative to a benchmark which, on the PGA Tour, would be an average PGA Tour shot. When the strokes gained values of many shots are grouped together a player can say, "These are my strengths and weaknesses." For a salesperson, it's not about how much revenue you brought in. You could have brought in $2.3 million, but an average salesman, given those clients in that territory, might have done 30 percent. You don't know what a number means without any context.
How has data and analytics affected the experience of watching sports for fans?
For fans, announcers, and writers it provides clarity that didn't exist before. I'm of the opinion that data and analytics enhances the experience by giving better context to what you're watching.
The appeal of sports for many fans is, in part, due to historical narratives and being able to compare players. Has the strokes gained method changed the way you think about golf history?
The shot tracking data that measures where shots started and ended has only existed on the PGA Tour since 2004, so it's hard to go back further than that with the same detailed analysis. However, you can get some historical insights and perspectives just using scoring data. One player could shoot a 72 and another could shoot a 69, but if they are at different courses, the 72 could represent a better performance than the 69. One way to place those two performances on a similar scale is to compare each score to the average score of the field at that course. So, if a player shoots a 69 and the average is 71.4, the player is said to have beaten the field. The strokes gained value is simply the difference between those two numbers, or +2.4 strokes in this case. That means the 69 was 2.4 strokes better than the field average. Every player in every round either “beats the field” or doesn't. If you're an average pro golfer, each round is a 50-50 proposition as to whether you beat the field.
I'm curious about records in golf, so I wondered who had the longest streak of consecutive rounds beating the field. We don't have all the scores for rounds featuring Jack Nicklaus, Ben Hogan, Johnny Miller, Arnold Palmer, and the other greats from the 50s, 60s and 70s. So, I went back to 1983, which is when scoring data on all the players in a field started to be compiled.
I asked a number people in the golf world, including some very famous players, who they thought owned the record for the longest beat-the-field streak. Most guessed correctly – Tiger Woods. But then I asked them about the length of the streak. Some guessed the longest streak was 20 or 25 rounds with the largest guess being about 30 rounds in a row. The real answer is astounding. At one stretch in his career, Tiger Woods beat the field 89 rounds in a row. For some context, the next closest is Mark O'Meara at 33.
What does the future hold for the use of data and analytics in sports?
In many sports, analytics is still growing because of the availability of new data, especially through player tracking. For example, in basketball, the NBA tracks the positions of all the players on the court and the ball 25 times a second.
There's even more interesting analysis that could be coming. Imagine a golfer who's wearing a fitness tracker. Now you could measure the pressure they feel, in part, by their heart rate. Putting a player's biometric information together with the action on the course or field makes for some fascinating possibilities.
Has strokes gained changed the way you watch the game, particularly when something is going awry on the course, such as Jordan Spieth's problems on the 12th hole in the 2017 Masters?
No, I'm watching as a fan and often rooting for players that I work with. But for me, it is a question of how extreme Spieth's performance was. Some of the research I'm doing now is about identifying and quantifying the greatest comebacks and the greatest collapses in golf.
I'm also looking at how to measure performance under pressure, without biometric data. In order to come up with a good statistic, it needs to combine performance and pressure in a way that's easy to understand for golf fans, players, and the media. It's not possible with all stats, but strokes gained has become widely accepted, in part, because it's accurate and easy to understand.