Expected Birdie Percentage

Expected Birdie Percentage
By Mark Sweeney and Jamie Donaldson

I tend to spend a fair amount of time looking at a player’s statistics in an attempt to really understand where their strengths and weaknesses are, particularly in the putting and scoring arena.  The primary stats we have to work with are GIR’s, Scrambling, Putts Gained, and Approach Shot Proximity, but I still often find I can’t quite summarize a player’s round from these.

For example, a player can hit 14 greens and shoot even par or shoot 6 under par, but what was the difference in performance that caused the difference in scores?  Putts Gained certainly helps to clarify his putting performance, but not his approach proximities.  And the Approach Proximity stat is just an average and doesn’t give birdie opportunities. For example an Approach Proximity of 25 feet doesn’t tell whether a player had only 25-foot birdie putts, or whether he had five 10-foot birdie putts and one 100-foot putt.

What I really need to understand comes from an idea I got from Dr. Bhrett McCabe called “In Position”, meaning how often when you hit the green were you in position to make a birdie (generally inside 20 feet).  If a player is hitting the green more than 20 feet from the hole, then he can’t be expected to make a lot of birdies.  In Position is a great stat to look at but I still want more—how close is a player hitting it and what are his expected number of birdies given his ball striking performance.

Lately Jamie Donaldson (Senior AimPoint Instructor for Europe) and I came up with some new metrics called the Expected Birdie Percentage (EBP) and the Actual Birdie Percentage (ABP).  The idea is simple: when a player hits the green in regulation, what were the odds of him making a birdie (EBP), and how did he perform relative to those odds (ABP)?

What we did is look at the probability of making birdies given the length of the player’s first putt after hitting the green in regulation, or his second putt if hitting a par 5 green in two shots (for now I’m ignoring chips-ins, hole-outs, etc.).  For example, a 3 foot birdie putt should be made 99% of the time, and a 15 foot birdie putt should be made about 24% of the time.  A player’s average make probability is his EBP.  A player’s actual make percentage of those putts is his ABP.

The results were interesting to say the least[1].  The players with the top 5 highest EBP’s are:

Rank Player Name EBP Driving Dist. Rank Money Rank
1 Watson, Bubba 39.5% 1 1
2 McIlroy, Rory 38.3% 5 28
3 Holmes, J.B. 36.2% 4 27
4 Johnson, Dustin 35.8% 2 3
5 Woodland, Gary 35.8% 15 25

All are very long hitters who can hit par 5 greens in two shots.  This finding supports Mark Broadie’s research in Every Shot Counts suggesting that long shots into greens are highly important, particularly the range of 175-225 yards.  What we may be seeing is that these are the big boy’s second shot into the par 5 greens, setting up eagles and easy birdies, versus long approaches into par 4’s which will generally lead to a two-putt par.

We can also look at how many birdies a player actually made after a GIR (ABP), and the top 5 players are:

Rank Player Name ABP Money Rank
1 McIlroy, Rory 41.8% 28
2 Schwartzel, Charl 37.8% 68
3 Woods, Tiger 37.8% n/a
4 Watson, Bubba 37.8% 1
5 Walker, Jimmy 37.7% 2

No big surprises there, but why is Woods ranked low in EBP and high in ABP?

Then we compare the expected birdie percentage (EBP) and the actual birdie percentage (ABP) and calculated the difference between the two into a metric we called Gain.  A players Gain is how many more percentages of birdies the player made above his expectation, due to putting.  The top 5 players in Gain are:

Rank Player Name Gain Putts Gained Rank
1 Woods, Tiger 11.5 n/a
2 Every, Matt 6.2 3
3 Walker, Jimmy 5.2 4
4 Donald, Luke 4.7 6
5 Loupe, Andrew 3.9 11

This means these players had the highest level of over-performance in making birdies relative to their ball striking proximities.  A Gain of 0.0 means you are meeting the tour average for converting birdie putts, while a negative Gain means you are under-performing and leaving birdies on the table.

These metrics can be very useful in understanding a player’s round because it gives a picture of how well he put himself in position to make birdies and how well he putted for birdies after a GIR.  Let’s take a look at Martin Kaymer’s rounds at The Players Championship:

Round EBP ABP Gain
1 44% 53% 8.8
2 32% 38% 6.9
3 26% 18% -7.7
4 34% 23% -11.3

His first two rounds were spectacular overall, and on the weekend he actually made fewer birdies than expected, even though every day except round 3 he put himself in great positions.

Remember these metrics are not meant to predict total score, just to give insight into a player’s ability to make birdies.  It also doesn’t take into account (at the moment) field putting averages on those days, just overall yearly putting averages.  If we look at the field averages for each round at The Players we see the following:

 Field EBP ABP Gain
Round 1 33% 32% -1.4
Round 2 29% 24% -5.7
Round 3 32% 33% 0.9
Round 4 32% 29% -3.1

In 3 out of 4 rounds players under-performed on the greens, possibly due to the putting difficulty, pin positions, weather, or faster green speeds at The Players.

The Expected Birdie Percentage is a method of evaluating a player’s chance of making a birdie after hitting a green in regulation–the higher the percentage the better his approach shots are.  Actual Birdie Percentage then shows his success in converting those opportunities into birdies.  It shows what birdie chances you are creating, how that compares to tour average, and how many of those you actually convert.  What the data suggests is that long hitters have a big advantage in scoring on par 5’s; if their birdie probabilities are higher than other players, they will make more birdies over a large number of rounds than the field.  The data certainly needs more detailed analysis, but this quick overview shows interesting patterns and can help players and coaches understand scoring a little better.

2014 EBP Rankings

EBP Rank Player Name EBP ABP Gain
1 Watson, Bubba 39.5% 37.8% -1.7
2 McIlroy, Rory 38.3% 41.8% 3.4
3 Holmes, J.B. 36.2% 35.1% -1.1
4 Johnson, Dustin 35.8% 34.9% -0.9
5 Woodland, Gary 35.8% 31.4% -4.3
6 Rose, Justin 35.5% 32.8% -2.7
7 Matsuyama, Hideki 34.9% 37.7% 2.9
8 Glover, Lucas 34.7% 28.2% -6.5
9 Ishikawa, Ryo 34.2% 34.5% 0.3
10 Schwartzel, Charl 34.1% 37.8% 3.7
11 Peterson, John 34.1% 27.6% -6.4
12 Scott, Adam 33.9% 36.8% 2.9
13 Streelman, Kevin 33.8% 33.8% 0.0
14 Palmer, Ryan 33.8% 33.5% -0.3
15 Bradley, Keegan 33.7% 33.6% -0.1
16 Mickelson, Phil 33.7% 31.7% -2.0
17 Kirk, Chris 33.6% 33.8% 0.2
18 Kaymer, Martin 33.5% 30.9% -2.6
19 Dufner, Jason 33.4% 33.8% 0.3
20 Spieth, Jordan 33.4% 33.4% 0.0
21 Kokrak, Jason 33.3% 34.4% 1.1
22 Noh, Seung-Yul 33.3% 30.4% -2.9
23 Matteson, Troy 33.2% 30.0% -3.2
24 Watney, Nick 33.2% 28.9% -4.2
25 Hoffman, Charley 33.1% 33.5% 0.4
26 La’Cassie, Bronson 33.1% 28.5% -4.6
27 Guthrie, Luke 33.0% 32.0% -1.0
28 Moore, Ryan 33.0% 32.3% -0.7
29 Garrigus, Robert 33.0% 34.8% 1.8
30 Bae, Sang-Moon 32.9% 32.8% -0.1
31 Chappell, Kevin 32.9% 31.4% -1.5
32 Westwood, Lee 32.9% 32.3% -0.6
33 Hadley, Chesson 32.9% 32.6% -0.3
34 Beljan, Charlie 32.6% 31.1% -1.5
35 Mahan, Hunter 32.6% 30.6% -2.0
36 Stanley, Kyle 32.6% 25.7% -6.8
37 Walker, Jimmy 32.5% 37.7% 5.2
38 Roach, Wes 32.5% 30.9% -1.6
39 Stadler, Kevin 32.4% 30.8% -1.6
40 Fowler, Rickie 32.4% 31.5% -0.9
41 Leishman, Marc 32.4% 30.8% -1.6
42 Wilcox, Will 32.3% 28.9% -3.3
43 Brown, Scott 32.2% 33.0% 0.8
44 Bowditch, Steven 32.2% 30.1% -2.2
45 Poulter, Ian 32.1% 32.4% 0.3
46 Fritsch, Brad 32.1% 26.9% -5.2
47 Stallings, Scott 32.1% 29.5% -2.6
48 Steele, Brendan 31.9% 32.1% 0.2
49 Reed, Patrick 31.9% 30.5% -1.4
50 Lovemark, Jamie 31.9% 29.7% -2.1
51 Jones, Matt 31.8% 32.9% 1.1
52 Austin, Woody 31.8% 29.0% -2.8
53 Horschel, Billy 31.8% 28.9% -2.9
54 English, Harris 31.7% 31.6% -0.1
55 Putnam, Michael 31.5% 27.5% -4.1
56 Colsaerts, Nicolas 31.5% 30.4% -1.0
57 Sabbatini, Rory 31.4% 29.7% -1.7
58 Herman, Jim 31.4% 27.1% -4.3
59 Cauley, Bud 31.4% 29.0% -2.4
60 Gainey, Tommy 31.4% 29.5% -1.9
61 Davis, Brian 31.4% 33.5% 2.2
62 Na, Kevin 31.3% 33.2% 1.8
63 Lee, Danny 31.3% 29.9% -1.4
64 Lee, Richard H. 31.3% 29.9% -1.4
65 Villegas, Camilo 31.2% 32.0% 0.7
66 Perez, Pat 31.2% 31.8% 0.6
67 Svoboda, Andrew 31.2% 31.1% -0.1
68 Simpson, Webb 31.2% 35.0% 3.9
69 Johnson, Zach 31.2% 32.3% 1.2
70 McNeill, George 31.2% 31.7% 0.6
71 Barnes, Ricky 31.1% 30.4% -0.7
72 Els, Ernie 31.1% 29.1% -2.0
73 Weir, Mike 31.1% 28.3% -2.8
74 Loupe, Andrew 31.1% 34.9% 3.9
75 Pettersson, Carl 31.0% 30.4% -0.6
76 Bohn, Jason 31.0% 31.2% 0.2
77 Chopra, Daniel 30.9% 31.8% 0.9
78 Stroud, Chris 30.9% 31.4% 0.5
79 Harman, Brian 30.9% 31.7% 0.8
80 Blixt, Jonas 30.9% 29.3% -1.6
81 Henley, Russell 30.9% 32.0% 1.1
82 Laird, Martin 30.9% 29.7% -1.2
83 Van Pelt, Bo 30.8% 28.2% -2.6
84 Compton, Erik 30.8% 30.7% -0.2
85 Hearn, David 30.8% 30.0% -0.8
86 Hoffmann, Morgan 30.8% 33.7% 2.9
87 Stuard, Brian 30.7% 32.4% 1.7
88 Casey, Paul 30.7% 33.4% 2.7
89 Byrd, Jonathan 30.6% 29.0% -1.6
90 Ernst, Derek 30.6% 26.1% -4.4
91 Weekley, Boo 30.6% 25.2% -5.4
92 McGirt, William 30.5% 29.5% -1.1
93 Love III, Davis 30.5% 28.5% -2.0
94 Haas, Bill 30.5% 29.7% -0.8
95 MacKenzie, Will 30.5% 33.5% 3.0
96 Koepka, Brooks 30.5% 30.7% 0.2
97 Baddeley, Aaron 30.5% 32.6% 2.1
98 Every, Matt 30.4% 36.6% 6.2
99 O’Hair, Sean 30.4% 27.5% -2.9
100 Teater, Josh 30.4% 28.2% -2.2
101 Romero, Andres 30.4% 32.0% 1.6
102 Huh, John 30.3% 27.7% -2.6
103 Oosthuizen, Louis 30.3% 29.5% -0.8
104 Overton, Jeff 30.3% 31.4% 1.2
105 de Jonge, Brendon 30.2% 28.7% -1.6
106 Campbell, Chad 30.2% 23.3% -7.0
107 Potter, Jr., Ted 30.2% 25.3% -5.0
108 Thompson, Michael 30.2% 32.9% 2.7
109 Snedeker, Brandt 30.2% 29.3% -0.9
110 Cabrera, Angel 30.2% 31.9% 1.7
111 Lingmerth, David 30.1% 31.5% 1.4
112 Maggert, Jeff 30.1% 24.8% -5.3
113 Streb, Robert 30.1% 31.9% 1.8
114 Duke, Ken 30.1% 28.4% -1.6
115 Aragon, Alex 29.9% 29.8% -0.2
116 Appleby, Stuart 29.9% 33.3% 3.4
117 Castro, Roberto 29.9% 28.7% -1.3
118 Howell III, Charles 29.9% 30.9% 0.9
119 Van Aswegen, Tyrone 29.9% 30.6% 0.6
120 Harrington, Padraig 29.9% 30.3% 0.4
121 Swafford, Hudson 29.9% 28.0% -1.9
122 Gardiner, Scott 29.8% 29.0% -0.8
123 Driscoll, James 29.8% 31.1% 1.3
124 Kuchar, Matt 29.8% 32.9% 3.1
125 Langley, Scott 29.8% 29.0% -0.8
126 Flores, Martin 29.8% 28.5% -1.3
127 Prugh, Alex 29.8% 26.8% -3.0
128 DeLaet, Graham 29.7% 27.7% -2.1
129 Kelly, Jerry 29.7% 29.8% 0.1
130 Kisner, Kevin 29.7% 30.2% 0.5
131 Senden, John 29.7% 30.2% 0.5
132 Yang, Y.E. 29.6% 29.2% -0.5
133 Toms, David 29.6% 28.3% -1.4
134 Thompson, Nicholas 29.6% 26.1% -3.5
135 Herron, Tim 29.6% 27.1% -2.5
136 Tringale, Cameron 29.5% 28.1% -1.3
137 Summerhays, Daniel 29.4% 30.0% 0.5
138 Vegas, Jhonattan 29.4% 26.1% -3.4
139 Wi, Charlie 29.4% 29.5% 0.1
140 Cink, Stewart 29.4% 28.9% -0.5
141 Merrick, John 29.4% 25.6% -3.8
142 Points, D.A. 29.3% 27.3% -2.0
143 Ogilvy, Geoff 29.3% 29.6% 0.3
144 Hahn, James 29.2% 28.5% -0.7
145 Choi, K.J. 29.1% 33.0% 3.8
146 Singh, Vijay 29.1% 25.6% -3.5
147 Chalmers, Greg 29.1% 32.8% 3.7
148 Todd, Brendon 29.1% 31.5% 2.4
149 Knox, Russell 29.0% 28.5% -0.5
150 Wilkinson, Tim 29.0% 29.8% 0.8
151 Immelman, Trevor 28.9% 26.8% -2.1
152 Frazar, Harrison 28.9% 26.1% -2.9
153 Garnett, Brice 28.9% 29.3% 0.4
154 Martin, Ben 28.9% 31.0% 2.1
155 Williams, Lee 28.9% 26.8% -2.1
156 Mallinger, John 28.8% 25.0% -3.8
157 Fdez-Castano, Gonzalo 28.8% 32.5% 3.7
158 Rollins, John 28.8% 26.2% -2.6
159 Merritt, Troy 28.8% 26.0% -2.8
160 Clark, Tim 28.7% 28.8% 0.1
161 Gay, Brian 28.7% 29.3% 0.6
162 McDowell, Graeme 28.7% 31.3% 2.6
163 Renner, Jim 28.6% 29.5% 0.9
164 Lee, D.H. 28.6% 28.2% -0.4
165 Levin, Spencer 28.6% 27.5% -1.1
166 Lynn, David 28.5% 30.3% 1.8
167 Hanson, Peter 28.4% 28.6% 0.2
168 Crane, Ben 28.3% 28.4% 0.1
169 Malnati, Peter 28.1% 30.1% 2.0
170 Baird, Briny 28.1% 27.5% -0.6
171 Ogilvie, Joe 28.0% 30.3% 2.3
172 Furyk, Jim 27.9% 25.5% -2.4
173 Jacobson, Freddie 27.9% 30.1% 2.2
174 Collins, Chad 27.7% 28.0% 0.4
175 Donald, Luke 27.7% 32.3% 4.7
176 Clarke, Darren 27.6% 23.3% -4.3
177 Molder, Bryce 27.6% 27.2% -0.3
178 Allenby, Robert 27.4% 26.8% -0.6
179 Goosen, Retief 27.2% 29.0% 1.8
180 Wilson, Mark 27.2% 26.0% -1.2
181 Durant, Joe 27.1% 24.0% -3.2
182 Hurley III, Billy 27.1% 26.8% -0.3
183 Gates, Bobby 27.1% 23.9% -3.2
184 Loar, Edward 27.0% 27.4% 0.4
185 Slocum, Heath 26.9% 26.1% -0.8
186 Hicks, Justin 26.9% 26.1% -0.8
187 Wagner, Johnson 26.8% 25.5% -1.3
188 Leonard, Justin 26.7% 28.3% 1.6
189 Henry, J.J. 26.6% 23.1% -3.5
190 Woods, Tiger* 26.3% 37.8% 11.5
191 Curtis, Ben 26.3% 28.3% 2.0
192 Tway, Kevin 25.8% 25.8% 0.0
193 Ames, Stephen 25.4% 25.6% 0.2
194 Goydos, Paul 24.6% 21.1% -3.5
195 Verplank, Scott 23.5% 21.8% -1.7

 

[1] data is from the 2014 season through the U.S Open, only players with at least 10 events plus Tiger Woods

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