[Steve Lang]

 

I was hoping the latest incarnation of YaBB would enable or promote some surveys being taken of folks here on GCA.COM..  till someone sets it up, I guess its got to be done the old way..  sooooo, what's your index?  How does the GCA.COM sample compare to the larger population?

Here's what the USGA says is the distribution of men's and women's indexes ( http://www.usga.org/handicap/articles/text/mens-hcap.html and http://www.usga.org/handicap/articles/text/womens-hcap.html)

Men's

USGA Hdcp Idx   Percent of Total   Cumulative
+1 or better   0.13%   0.13%
0   0.55%   0.68%
1   0.57%   1.25%
2   0.85%   2.10%
3   1.15%   3.25%
4   1.56%   4.81%
5   2.02%   6.83%
6   2.56%   9.39%
7   3.17%   12.56%
8   3.68%   16.24%
9   4.20%   20.44%
10   4.66%   25.10%
11   5.02%   30.12%
12   5.41%   35.53%
13   5.58%   41.11%
14   5.67%   46.78%
15   5.54%   52.32%
16   5.36%   57.69%
17   5.02%   62.71%
18   4.64%   67.35%
19   4.23%   71.57%
20   3.88%   75.45%
21   3.46%   78.91%
22   3.12%   82.03%
23   2.78%   84.81%
24   2.44%   87.25%
25   2.11%   89.36%
26   1.81%   91.17%
27   1.54%   92.71%
28   1.30%   94.01%
29   1.10%   95.12%
30   0.91%   96.03%
31   0.75%   96.78%
32   0.61%   97.39%
33   0.51%   97.91%
34   0.42%   98.32%
35   0.34%   98.66%
36+   1.34%   100.00%

Women's

USGA Hdcp Idx   Percent of Total   Cumulative
+1 or better   0.03%   0.03%
0   0.05%   0.08%
1   0.05%   0.13%
2   0.08%   0.21%
3   0.10%   0.31%
4   0.15%   0.46%
5   0.18%   0.64%
6   0.24%   0.87%
7   0.31%   1.18%
8   0.40%   1.58%
9   0.51%   2.09%
10   0.61%   2.70%
11   0.76%   3.46%
12   0.97%   4.43%
13   1.22%   5.65%
14   1.41%   7.06%
15   1.71%   8.77%
16   1.92%   10.69%
17   2.20%   12.89%
18   2.38%   15.27%
19   2.55%   17.82%
20   2.76%   20.58%
21   3.06%   23.64%
22   3.40%   27.03%
23   3.67%   30.70%
24   3.87%   34.57%
25   3.98%   38.55%
26   4.08%   42.63%
27   4.09%   46.73%
28   4.15%   50.87%
29   4.03%   54.91%
30   3.98%   58.89%
31   3.83%   62.71%
32   3.74%   66.46%
33   3.54%   70.00%
34   3.32%   73.31%
35   3.11%   76.43%
36   2.85%   79.28%
37   2.60%   81.88%
38   2.30%   84.18%
39   1.98%   86.16%
40+   13.84%   100.00%


I'm a 5.8 at best, going to a 9 or so next week..

[ed_getka]

The only index I worry about is the fun index & I doubt most golfers have more fun than we do. It is so cool to golf together with guys who are on the same wavelength.

[Steve Lang]

Shivas.. do we take that as you used to be a 1 and now a 6+???

[Martin Del Vecchio]

Shivas, when comparing historical handicap averages, you must also take into account the population.  I don't have any figures, but I think it's safe to assume that the handicap population has changed quite a bit in the last thirty years.

If a larger percentage of golfers now carry a handicap, and if that increase has occurred more in the public and muni clubs, then it is possible for the average handicap to remain constant.  At the same time, it is also possible that the population of golfers who have maintained handicaps for the last 10 years has gone down.

[Martin Del Vecchio]

PS  I think the USGA table shows that the median handicap is somewhere between 14 and 15, but doesn't reveal what the average handicap is.

[Scott_Burroughs]

Shivas,

Without getting out a calculator to figure out the mean, you're probably thinking of the median handicap, which is 15 in this case.  1/2 of all players are below, half are above (or tied in this case).

Looking at the distribution of the percentages, the mean would be higher than the median because "upper tail" of the distribution is longer, with number of high handicaps (30+) skewing the mean above the median.

[ForkaB]

Shivas, et.al.

One thing not mentioned is the difference between one's handicap index (which the USGA stats report) and actual handicap, which requires adjustment for slope.  Most actual handicaps are higher than the index (as the "average" slope of 113 is not an average at all, but more of an arbitrary constant).  In fact, Shivas, given the difficulty of the courses you play and the fact that you are playing from the tips all the time, I'd guess that your index of 6 would translate closer to an 8 on most course.  Given your talent, if I were you I'd play with the old clubs and forget about the evil sticks in your wife's truck whcih are obviously part of the problem and not a part of the solution!

[Scott_Burroughs]

Rich,

I believe 113 was at one point the average slope rating of all  courses at the time (however many years ago that was).  With seemingly every course being built today having a slope in the 130's at the minimum, the avg slope surely has risen.

[JohnV]

113 is the mid-point on the scale.  It is not and has never been the average of all slopes in the US.

[Scott_Burroughs]

Thanks for the clarification, John.  I knew there was a reason it was 113 and not 'arbitrary'.

I still think a true average or median would make a little more sense, but what a handicap is (a measure of your potential, not average score above par) still confuses people.  That's why people rarely shoot their handicaps.

[A_Clay_Man]

analysis would be productive if 'all things were equal'. Wht's missing from the data is the individuals propensity to be either a sandbagger(cheats others) or an ego capper who only posts his good scores. It could be assumed that they are both equal and therefore cancel each other out, but, after this weekend's club championships here, the evidence is that the ego cappers out weigh the baggers. There was a 14 who shot 104 & 103 and had no ettiquitte and held up the whole show. (Obviously the 14 failed to count all those pesky penalty strokes when left to his own honor.) In the Champ flight several players shot 90 or higher.  Meanwhile, there was one 10 who shot 74,& 73 to win the gross enchilada. He's from Thousnad oaks and knows Rustic canyon well. Does this prove the early worthiness of Rustic Canyon's ability to produce champions? Long and down the middle can be highly overated. cain't it?

[JohnV]

Scott, I actually mistyped.  113 is not the "mid-point" of the scale since it runs from 55 to 155.  According to the USGA Handicap Manual, "A golf course of standard playing difficulty has a USGA Slope Rating of 113."  I've never understood why they couldn't fudge the number to make it 100.  It would have made the calculation so much simpler.  Then, if you played a course with a slope of 127 you would just multiply your index by 1.27 instead of 127/113.

[Scott_Burroughs]

Hmmm.  Maybe I was right after all.    Assuming standard=average, that is.  100=standard/average in IQ's.

[ForkaB]

Scott

Actually I think John's elucidations prove that I was right!   ;)All that 113 represents is the sum of the midpoints of a bunch of separate calculations dreamed up by Dean Knuth many years ago.

As John has explained on here before, the actual calculated slope for any set of tees represents the ratio between the course "bogey" rating (i.e. what a "bogey" golfer would score) and its course rating (i.e. what a "scratch" player would score).  Now, if the "average" slope is 113, this would assume that a bogey golfer would score 13% higher on that "average" course than the scratch player.  If we assume that the average course has a par and course "rating" of 72, this means that the "bogey" player is going to shoot 72*1.13, or 81 on this average course.  If there are such bogey players out there in the world, give them my phone number for I want THEM as partners when I play for money!

John

Have I missed something?

[Scott_Burroughs]

Rich,

Wouldn't a bogey golfer shoot a 90 on an average course?  (+1 * 18) + 72 = 90.  90/72 * 100 = 125.

[John_Conley]

This discussion brings up a good point.  As players are hitting the ball longer, the courses seem to have maintained the same scoring average because of a more difficult set-up.  New, modern courses are so fraught with danger that it is hard to shoot the same score you can on an older style design that's set up the same way it was 30 years ago.

[ForkaB]

Scott

As I interpret what John and others have told me, the "bogey" course rating on a course with a slope of 113 and a "scratch" course rating of 72.0 would be 72.0*1.13 = 81.4,  but, I could be wrong......

[JohnV]

Rich,

Yes, you have missed something.

Slope = Course Rating - Bogey Rating * 5.381 (for men)
so,
Bogey Rating = Slope/5.381 + Course Rating
Bogey Rating = 113/5.381 + 72.0
Bogey Rating = 93

So, a bogey golfer would average about 93 for his 10 best scores on a course rated 72 with a slope of 113.

The slope is just the value of the rise over the run of the various scores vs indexes.

In other words, the harder the course the faster the difference between indexes increases therefore the higher the slope of the line.  If you plot scores on the Y line and indexes on the X line you would see different lines occuring for courses of different difficulties.  The ratio between how fast the scores go up as the indexes change is the slope.

Dean Knuth, who invented the slope system, determined that a course with standard difficulty would have a slope of 113 so if you play a course that is harder than that you get more strokes and if you play one that is easier, you get less.

[Bob_Huntley]

The USGA handicapping system is as arcane as some of the theology of Bonhoeffer's Discipline.

Rihc and I agree on this and feel that we should eliminate the 113 figure and simplify by using a 100. Better yet, stop this insane practice of having golfers putt out for a six when an opponent has a certain birdie. Think of the time saved by picking up and ceding the hole.

[ForkaB]

Thanks, John.  I think your initial equaiton is a tyop, but I get the gist of the calculations.

PS--when the "Pope of Slope" determined the coefficient of 5.381, did he do so scientifically, or was he just guessing?

[THuckaby2]

Now THAT is the $128,000 question here (adjusted for inflation).  Where the hell does that 5.381 come from?

I've done pretty well figuring out all the rest of the weird math our handicap system provides... that one has always stumped me though.  John V. - any thoughts?  There's sure as heck no explanation on popeofslope.com....

TH

[Steve Lang]

  5.381802397519751845918465

It all seems like insignificant digits!

Taking the +/1- sandbagger factor as a given, .. it would seem all of the bases of the past, including the majic "113" constant need revisiting.

On the gradual shift in median values contemplated by some.. I for one didn't have a home course based handicap till 12 years ago.. never needed one for games where numbers float with bets.  I suspect the coolness factor now of golf has added more young folks into the system versus older club types..

[JohnV]

To quote an article I found on myscorecard.com:

Why 5.381? Using this number as a multiplying factor will produce Slope Ratings of 113 when the differential between the Bogey Rating and Course Rating is 21.0 (The expected difference in score on an average course between our model scratch golfer and bogey golfer with handicap between 17.5 and 22). A Slope of 113 (actually 1.13) also is the empirically derived regression value of scores played on standard American golf courses. So it all ties together.

To read more see MyScorecard.com

I don't claim to understand all of the above, but I believe that there was a lot of mathematical thinking involved and not just some number pulled from the nether regions.  By the way, the number for women is 4.24, which was evidently derived in a similar manner.

[THuckaby2]

Aha!  Thanks, JV... so this goes back to 113... they use 5.381 only to produce the 113 number... which begs the question why 113 and not 100...

Oh well, never mind.  Thanks for trying anyway!

Bottom line here is that all this arcane math does produce decent enough results.  I'm happy enough with that.

TH

[John Foley]

I happened to play a course yesterday and was puzzled by the fact the their slope had increased from a 121 to a 132 from the last time I was there. The only architectural differences was thinning of some tree's (YEAH!!) and a new tee box which is about 6 feet higher than the old. Hole still plays to the same distance. What is the reason for such a dramatic change. From John V's description I would infer that more bogey golfers are playing worse and/or the better golfers are  playing better? The change in slope of 11 pts seems to me to be a large jump.

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