September 27, 2017
By Matt and Will Courchene, PGATOUR.COM
- Is there a science behind the strength of the field at any given event? (Kevin Cox/Getty Images)
What are the strongest fields in golf?
First, let’s define a measure for field strength; we measure the strength of a field by the quality of the average player in that field. Therefore, our measure does not (necessarily) capture the difficulty of winning an event.
You will see that the 2017 TOUR Championship had a very strong field, by our measure. This is because the average player quality in that field is very high – and yet, because the field size is so small (30 players), the tournament itself theoretically is not as difficult to win as a tournament with, say, 156 players in the field.
To measure player quality, we calculate each player’s adjusted scoring average (adjusted for course difficulty) in the year 2017. We normalize all scoring averages so that they indicate how many strokes better a player performed than the average player in a regular PGA TOUR event (i.e. non-major, non-WGC). The strength of a field is then defined as the average of the adjusted scoring averages for all players in the field.
For example, if we had a field consisting of just two players, Jordan Spieth and Dustin Johnson, then field strength would be calculated as follows: we average Spieth’s adjusted scoring average for 2017 (+2.8) and Dustin Johnson’s adjusted scoring average for 2017 (+2.3) to obtain a value of 2.55. Then, to interpret the strength of this hypothetical field, we would say “the average player in this field beats the average player in a (non-major/WGC) PGA TOUR field by 2.45 strokes per round.”
The following table shows the average field strength of all events on various tours in 2017. We separate the majors and WGC events into their own categories, as they contain players from several different tours.
|TOUR/EVENTS||AVG. PLAYER STRENGTH|
|World Golf Championships||0.76|
|PGA TOUR (non-major/WGC)||0.00|
|PGA TOUR Champions||-2.89|
|Sunshine Tour (South Africa)||-2.93|
|ISPS HANDA PGA Tour of Australasia||-3.13|
Note: Values are interpreted as the number of strokes per round better (+) or worse (-1) than the average player in a regular PGA TOUR event.
Notice that the value for regular PGA TOUR field strength is zero; this, of course, is because we have defined our scoring average measure relative to the average player in a non-major/WGC PGA TOUR event. To clarify with another example, the above table tells us that the average player in a PGA TOUR Champions event is about 2.9 strokes worse per round than the average player in a regular PGA TOUR event. This may seem like a lot, but keep in mind that the gap between the very best players and the average player on the PGA TOUR is about 2.5 strokes per round.
You may wonder how we can compare scoring averages across all these tours, given that not all players directly compete against each other. The key is that we have overlap between fields on all tours; a PGA TOUR Champions player competes in events against, for example, Steve Stricker, and Stricker also competes in events against PGA TOUR players.
So, through their performances relative to Stricker, we can compare players’ performances on PGA TOUR Champions to players’ performances on the PGA TOUR, even though they never directly compete against each other (for more info on this statistical method, see here (provide link: http://datagolf.ca/an-intergenerational-approach-to-ranking-pga-tour-players/))
Next, here is a list of the strongest fields in our sample of events in 2017. In addition to overall field strength, we provide the strength of each quartile of the field. For example, top 25 percent field strength is the average of the adjusted scoring averages belonging to the best 25 percent of players in the field. The other percentage breakdowns are defined analogously.
For the full list of events in the interactive table, click here.
To finish off, we provide a breakdown of the strength of each team in this week’s Presidents Cup. Given that there are 12 players aside, each quartile is the average of just 3 players.
We see that the American team is stronger across the board, but the greatest difference is at the bottom end: the three lowest American players are 0.87 strokes better per round than the three lowest International players.
Brothers Matt and Will Courchene grew up in a Canadian household full of golf fanatics. In 2016, they launched a DataGolf blog in hopes of contributing fresh and unbiased insights to the sport.
Matt, a PhD student at the Vancouver School of Economics, focuses on applied econometrics and causal inference, while Will, who has a Masters of Economics from the University of Toronto, focuses on statistical modeling and data visualization.