The New Statistic, Part II

Last spring I wrote about a new statistic I devised called shot efficiency.  The idea was to try to analyze ball striking for a round, using a few simple numbers (course rating, yardage, score, and putts.  [See the post for the full formula.]  One of the flaws inherent in the formula is it doesn't fully account for how challenging a course is to play -- something that is fundamentally accounted for in the "other" part of the USGA course rating system, the slope.

The USGA suggests that the best way to determine how difficult it is to score on a given course or set of tees is to use the bogey rating.  Here's how they explain it:

This rating is the evaluation of the playing difficulty of a course for the bogey golfer. It is based on yardage, effective playing length and other obstacles to the extent that affect the scoring ability of the bogey golfer. To figure out this number, other than from looking at this database, the bogey golfer should take the Slope Rating®, divide it by the set factor (5.381 for men, and 4.24 for women) and add that to the Course Rating. The result is a target score for the bogey golfer, and is a truer yardstick of the challenge that lies ahead for the particular set of tees. Example: 96.3- which predicts the bogey golfer's average of his ten best (out of twenty) scores would be approximately 96.3 from this particular set of tees.

So how can we use this to adjust the shot efficiency formula?  The first step I came up with is to determine what I'm calling the course adjustment factor (CAF):

CAF = BOGEY RATING / STD BOGEY RATING

 where:

BOGEY RATING = [SLOPE / 5.381] + COURSE RATING

STD BOGEY RATING = [113 / 5.381] + COURSE RATING

I use 113 as the "standard slope" as that is the USGA definition of an average difficulty course.  From there I simply multiply the calculated shot efficiency by the course adjustment factor to yield the adjusted shot efficiency (ASE).

As an example, let's look at 3 rounds that have the same shot efficiency score to see how the adjustment impacts the rating.  As it turns out, I shot 79 in all 3 of these rounds, making it an even more ideal comparison:

1. 4/29/09 at Butter Brook Golf Club (Black Tees, 6702 yards, 72.6 rating, 133 slope).  I shot 79 with 30 putts, for a SE of 0.737.  The CAF comes out to 1.046, so the ASE is 0.771.  By the conventional metrics I hit 54% of fairways and 50% of GIR.

2. 8/2/09 at Brookmeadow Country Club (Gold Tees, 6585 yards, 71.7/123).  Again shot 79, this time with 31 putts, again the SE being 0.737.  The CAF for those tees is 1.017, so the ASE this time is 0.749.  The standard stats: 29% fairways and 44% greens.

3. 3/6/11 at Nancy Lopez Legacy CC in the Villages (Black Tees, 6906 yards, 73.2/135).  Shot 79 with 29 putts for (again) a SE of 0.737.  Here the CAF is 1.057, for an ASE of 0.779.  In that round I hit 50% of fairways and 33% of GIR.

Obviously these three rounds are all quite similar, but the intuitive difference that comes from the course difficulty is fairly represented by the subtle difference in the adjusted shot efficiency.  

Here's an even better example: in my 2008 round at Bethpage Black, I shot 94 with 36 putts, for a SE of 0.687.  The Black is largely considered one of (if not the) most difficult courses in the country, with a rating (at that time) of 76.6 and a slope of 144.  It's a great course to empirically understand how the slope rating works; even though the course is incredibly long, it plays even longer because of elevated greens, thick punishing rough, and the maniacally placed bunkers -- hence a high slope rating.  So when you apply the course adjustment factor (the highest of any course I've played at 1.123), the ASE jumps all the way up to 0.771.  And that's fair -- there's no way you can say an 84 at Braintree Municipal (rated at 70/123) has an equal shot efficiency to 94 at Bethpage, but that's how the calculation works out.  After applying the course adjustment, the difference in the 2 rounds is almost 10% (0.771 vs. 0.686).

On a final note, here are my top 5 rounds by adjusted shot efficiency over the past 3 years:

1. Butter Brook (7/17/11): score 73 (+1), SE 0.926, ASE 0.969.
2. Cane Garden (5/18/10): score 80 (+8), SE 0.868, ASE 0.925.
3. Granite Links (7/29/10): score 76 (+5), SE 0.851, ASE 0.913.
4. Red Tail (7/25/09): score 75 (+3), SE 0.851, ASE 0.911.
5. Butter Brook (6/23/10): score 74 (+2), SE 0.860, ASE 0.900.

Up next in the statistics category, I'll try to tackle the other part of the game: short game/putting.  

The Heat (The Humidity)

Maybe I'm getting old.

Maybe it's that my back and shoulders don't loosen up as easily when it's cool out.  Maybe I'm like a Dominican pitcher who only gets going when the summer weather rolls in.

Just call me Pedro.

click for larger image

For some reason, I play my best golf in July.  There's really no question about it.  See the chart on the right side -- I'm almost a full 2 shots better on average in July as compared to any other month.  I seem to have a "hot streak" almost every year in July when I feel like even par is legitimately in play almost every time I take to the course.  In 2009 I whipped off 78-77-75-74 over an 8 day span; in 2010 I had rounds of 75, 76, 77, 78 and 79.  And almost every one of those rounds has been played (at least as far as I remember) in sweltering heat.

The past 2 days have been 85-95 degrees and very humid in the Boston area.  And I'm +8 over 36 holes during that time span.  Yesterday, at Butter Brook, I shot 73.

Yes, that's right, +1.

I don't want to go through the hole round blow-by-blow, but thinking back on it there were a few key shots:

2ND HOLE, 1ST PUTT  After making bogey on the 1st, I hit 5 iron to the middle of the fairway and 8-iron to pin-high about 18 feet from the hole.  I putted that one a good 15 feet past, and missed the come-back for a dreaded 3-putt.  Grrrrrrrrr. (+2 for the round)

4TH HOLE, APPROACH SHOT  After hitting the right side of the fairway on the dogleg left, I pulled a 6-iron into the greenside bunker, leaving myself short-sided with a bad lie in the sand.  I got out of the trap but had an impossible putt (from the top of a ridge about 25 feet across the green with the cup about 3/4 of the way down a hill.  And... I hate 3-putts!!!  (+4 for the round)

8TH HOLE, TEE SHOT  The par-3 was playing at about 165 yards with the pin in front, slightly down wind.  I hit 7-iron directly at the stick; it landed about 6 inches in front, bounced and then spun just a bit to the side, 3 inches from the hole.  There were 2 members of the grounds crew up watering the green at the time; both said they couldn't believe it didn't go in.  Closest I've ever been to an ace.  (It turned out, by the way, that the two on the green were, in fact, the owners.)  (+2 for the round)

16TH HOLE, 2ND SHOT  After reeling off 10 straight holes at par or better (-2 over that stretch), I had just made a bogey on the difficult par-4 15th and stood at +3 on the 16th tee.  The odds were against me, but eagle on the par-5 16th (which I'd managed before) would go a long way.  My drive, unfortunately, did not go a long way -- only about 225 yards, but in the middle of the fairway.  According to my GPS I had 277 to go, which meant I didn't have enough club unless I got a real favorable roll out.  I went with 1-hybrid because the trajectory would be low and I usually do get a lot of top spin; maybe -- just maybe -- it would get me home or close to where I could chip in.  I told myself to stay smooth, don't overswing (because that almost always gets me to snap-hook with my hybrids)... and I pured it.  I watched at it sailed down the right side and caught the slope from there and ran toward the green.  From my position on the fairway it looked pretty good, but I couldn't tell for sure if it got home or not.

It was home.  3 feet from the pin.  Tap in eagle.  (+1 for the round)

I needed to get up and down
from 82 yards in a bunker.

18TH HOLE, PUTT  I made a fairway-green-2-putt par on 17, which meant it would take birdie on the 18th to get to even par.  I do not play the 18th hole at Butter Brook well (average 0.9 strokes over par, with 4 double-bogies or worse in 17 prior rounds from the black tees).  To make matters worse, my tee ball settled in the fairway bunker about 85 yards out on the right side.  I hit about as good a shot as I could from there, pitching wedge to the middle of the green, 22 feet from the hole (I paced it off).  The putt was a double breaker -- slightly uphill and left-to-right over the first two thirds, and then just downhill and right to left over the last 6 or 7 feet.  I picked a line that was starting about 6 inches left of the hole... and that's almost exactly where it ended up, 6 inches left.  Oh well.  +1.  (Shot efficiency 0.930, my personal best.)

This was the putt left for even par.

Hopefully I won't have to wait until next July to come that close again.

The Photo Shoot

Going to do something a little different for this blog entry.  I played Butter Brook today (shot 80, was +3 after birdie on the 12th, but triple bogey on 13 was again my undoing; shot efficiency 0.698).  But I also brought my camera along, and instead of boring myself with the blow-by-blow, let's just look at some shots of a different type.

Butter Brook | 6th Green

Butter Brook | 7th Fairway

Butter Brook | 8th Tee

Butter Brook | 10th Tee (B&W)

Butter Brook | 12th Green

Butter Brook | 15th Green | The Pump House

Butter Brook | Kennedy Bros.

Butter Brook | 16th Green

Butter Brook | 17th Tee | "Intimidation"

Butter Brook | 18th Green

The One Hole

Ah, golf is a fickle game. 

Yesterday, as I stood over a putt on the 12th hole at Butter Brook, I was 100% convinced that I was going to shoot even par -- or better.  Everything was clicking.  It had been a virtually perfect round up to that point. 

But all good things do come to an end.