Statistics have always played a part in the analysis of golf and its golfers. They allow comparisons to be made between individuals with all their varied characteristics, abilities and experiences, enabling a golf coach to use those statistics to drive action.
The amount of information and number of statistics/metrics available to the Professional coach has never been greater – in fact, many argue that there is too much information out there that does not answer the questions people really want to know about.
This is something that Columbia Business School Carson Family Professor of Business and keen golfer, Mark Broadie, saw as being fundamental to his groundbreaking research in the past 10 years. Current statistics and metrics are good but lack the capability in many cases to relate other metrics. In response to this he developed a system that allows all the elements of the game to be compared to each other – Strokes Gained.
In his new book, ‘Every Shot Counts’, Broadie explores his Strokes-Gained metric that has entered the public consciousness through use of Strokes Gained – Putting on the PGA Tour, and the overall research that has led to a fundamental change in our understanding of how important the different areas of the game are.
IGPN: The Strokes Gained statistic is really a completely different way of assessing the performance of a player on the course – how did you come up with the concept for it?
MB: I started by asking ‘what separates an ‘80’ and a ’90’ golfer – where do these 10 strokes come from?’ Another question was how to grade a golfer in different areas; long game, short game, sand play, approach shots, driving – how could you compare all those things?
There are a lot of ways you could do this – such as how close do they put approach shots to the
“About two-thirds of a 10-stroke difference comes from shots outside of 100 yards and about one-third comes from shots inside 100 yards…that’s pretty robust across hugely different skill levels”
hole? If you have a large enough data set then you can see that this person’s average score might be 80 but they’re hitting their approach shots like a scratch golfer, or they may be hitting relatively poor approach shots like a ‘90’ golfer.
The problem is that these measures still don’t answer the question of where do the 10 strokes between and ‘80’ and a ‘90’ come from? In order to answer that question you need to be able to compare drives that are measured in yards/meters with something like greens in regulation which is either ‘yes you hit it’ or ‘no you missed.’ You have all these different ways to measure golf but they don’t answer the question about where that scoring difference comes from.
In order to do that you need to be able to measure say driving distance and driving accuracy on a scale that’s comparable to sand play or to putting, and it turns out how to do that is to measure everything in strokes – and that led to strokes gained.
The idea was that you could measure the quality of every shot from a drive to an approach shot, or a sand shot to a putt in this consistent unit of strokes gained – it allows you to measure all parts of the game together.
IGPN: And the PGA Tour have used the putting element of your research…
MB: I had written an article and then presented at the World Scientific Congress of Golf in 2008 with some early findings on this notion of strokes gained applied to the entire game. A couple of years later I was at a conference with a group from MIT [The Massachusetts Institute of Technology] and the PGA Tour was there just letting academics know that this is what their ‘ShotLink®’ data is and how it’s available to academics through their ‘ShotLink® Intelligence Programme’. So we presented our work there…[and] that sort of crystallised things at around the same time that the PGA Tour internally was saying ‘we need to come up with a better putting statistic because putts-per-round’s deficiencies were obvious to them.
What the PGA Tour implemented in 2011 was just the ’Strokes Gained – Putting’…I had been looking at short, medium and long putts [to] break it down into sub-categories, but the PGA Tour’s reaction was ‘no, no, the problem is we have too many stats’. They have putting from four-feet, five, six, seven, eight, etc. – so in a way they have too much and too little.
Part of the reason for this book is to let people know that this analysis applies to all parts of the game and that the PGA Tour’s aim has always been to roll out more strokes gained stats in the future. They are planning on rolling out ‘strokes gained – tee to green’ next. On a TV broadcast or leaderboard at a tournament… you could have ‘total stokes gained’ broken down into tee to green play and putting. That would allow you to see on why somebody is leading or why somebody is only in 10th or 20th place.
Strokes Gained – Putting Example from the PGATour.com:
|Putts gained(From given distance)||=||PGA Tour Average putts taken||–||Actual putts taken to hole out|
The statistic is computed by calculating the average number of putts a PGA TOUR player is expected to take from every distance, based on ShotLink® data from the previous season. The actual number of putts taken by a player is subtracted from this average value to determine strokes gained or lost. For example, the average number of putts used to hole out from 7 feet 10 inches is 1.5. If a player one-putts from this distance, he gains 0.5 strokes. If he two-putts, he loses 0.5 strokes. If he three-putts, he loses 1.5 strokes.
A player’s strokes gained or lost are then compared to the field. For example, if a player gained a total of three strokes over the course of a round and the field gained an average of one stroke, the player’s “Strokes Gained Against the Field” would be two.
IGPN: Your research revealed that when you look at all these areas together the relative impact of each area of the game was actually different to traditional thinking – the differences between ‘80’ or ‘90’ golfers, or even between good tour players and the best players, were more because of the long game…
MB: Roughly about two-thirds of a 10-stroke difference comes from shots outside of 100 yards and about one-third comes from shots inside 100 yards and that’s pretty robust across these hugely different skill levels.
There are definitely differences amongst individuals – I’m talking about a typical ‘80’ golfer versus a typical ‘90’ golfer, or a typical professional golfer versus typical top-10 professional.
IGPN: So the traditional emphasis on putting, or at least the general tendency towards ‘drive for show, putt for dough’, is not accurate – what sort of reaction have you had to that?
MB: I’ve heard more from the people that agree with the findings in the book – people are saying ‘finally, I’ve thought this all along’ – and probably a little less from the people that disagree.
I tried in the beginning of the book to figure out what are the strongest arguments that people have for the importance of putting – I tried to say why I thought the arguments fell short, but I’m certainly interested in trying to speak to anyone that has a different view.
A lot of people have pointed to Tiger Woods and have said that the main factor that explains his success is his putting. The reason that seems plausible is that he’s such a good putter – the data bears that out, but he’s also good at everything else, it’s just approach shots where he really dominates. He’s great at everything but really great at approach shots. It’s a surprise to a lot of people but not someone like Sean Foley, his coach.
“Tiger’s approach shots are where he really dominates, he’s great at everything but really great at approach shots. It’s a surprise to a lot of people but not someone like Sean Foley”
The other thing I’ve found is that when you look at PGA Tour winners, the explanatory power of putting is higher. Using 10 years of data, I find that putting contributes about 15% of the scoring advantage of the best Tour players compared to average Tour players. If you look at tournament winners then putting contributes about 35% of the scoring advantage during their wins.
Part of the reason is that when you look at tournament winners, then there’s a different one every week, and whoever wins that week is someone who’s playing well above their norm.
That’s part of the reason that people tend to believe in the importance of putting – they see putts going in from all over the planet when they watch the highlight reels of someone winning a tournament but they don’t show the shots that get them there.
IGPN: You spoke recently at an MIT Conference with Tiger Woods’ and Justin Rose’s coach, Sean Foley, about how he and other coaches can turn the data produced using strokes gained into actionable data and also on the statistical approach coaches should have – what do you think are the main ways a coach can use this type of information?
MB: It’s deﬁnitely easier for coaches whose pupils are PGA Tour golfers because of the ShotLink® data that’s available…the PGA Tour records all of the shots of all of the players at all PGA Tour events. You can break down a golfer’s strengths and weaknesses fairly accurately [using strokes gained] and that allows a coach like Sean Foley to focus his instruction on what will give the biggest bang for the buck.
It would be ideal if amateurs went to their instructors with strokes gained reports, which detailed their trends, strengths and weaknesses. It is possible for amateur golfers to collect data on their own shots, using lasers or yardage books, and then use the tables in the book to do the strokes gained analysis on their own. We’re working on an app that I am hoping will be ready for beta-testing in two or three months that will make it even easier for individuals to do it themselves.
You want to make it as painless as possible for golfers to record their shot information – the PGA Tour pros have it great because someone else is doing it for them – but for amateur golfers data entry is the hurdle. The good thing is it’s really not that painful for an amateur to record their own data – I’ve been doing it for years and the app will make it even easier. In my database of amateur golf shots, it shows that putting contributes about the same to scoring differences as it does for the pros. But every golfer is unique, and having strokes gained report for individual golfers would be, I think, quite useful for coaches.
The book shows how you can go out to the practice green or short game area and test your skills by hitting a bunch of putts and shots. There are tables in the book where you can compare yourself to pros and amateurs of various levels. It’s fun and you can do it in a short period of time, an hour or so, though it has the disadvantage that it’s not in tournament play and it’s not in the changing conditions that you might get on the course.
In EVERY SHOT COUNTS: Using the Revolutionary Strokes-Gained Approach to Improve Your Golf Performance and Strategy (Gotham Books, March 10, 2014, Hardcover, eBook) Broadie explains the simple idea behind strokes gained and shows how it applies to all golf shots. He uses it to answer many questions of golf performance: What does it take to win a PGA Tour tournament? What is the secret behind Tiger Woods’ success? Which skills separate amateurs from pros? How much is twenty extra yards of driving distance worth?
EVERY SHOT COUNTS also uses this new data to analyze golf strategy: Lay up or go for it? Play an aggressive or conservative shot off the tee? Not a book about swing mechanics, EVERY SHOT COUNTS uses data and analytics to better understand golf performance and golf strategy. EVERY SHOT COUNTS reveals truths that will change the way golfers of all handicaps look at and play the game.