Handicap Insanity.......................

[BuckeyeNut]

I've kept a valid HC for decades and I don't really know if I understand the inner workings of it all...LOL

This is what I think I know::::::::::

CR is the determining factor to calculate HC index...as far as I know it's 100% of the index (possibly not)

The Slope rating determines the course HC....100%

To me this makes no freakin' sense!!  Does slope play a hidden role in calculating the differential/index number?  I really don't know, but it must?!!

For example......what if I score 80 on 2 courses......

74.5CR 125 slope

74.5CR 145 slope.......

Will the differential be different?

I've been playing for a long time, and I am almost embarrassed that I do not know!!

So...c'mon experts!!

[RickK]

Yes. it will be different.  on the 125 slope rating, your differential will be 5.0 but on the 145 slope rating, your differential will be 4.3.

Subtract the course rating from your adjusted gross score and you get 5.5 in both cases.

Multiply 5.5 by the standard slope rating of 113 and in both cases, you get 621.5.

Now, here is where slope rating comes into play.

Divide 621.5 by the actual slope rating for the course.

For 125, you get 5.0

For 145, you get 4.3

Hope this helps.

BTW, I'm no expert.  I just read the formula a couple of years ago and built an Excel spreadsheet to calculate it.

[BuckeyeNut]

Im not sure if you answered the question. LOL

[Golfingdad]

Im not sure if you answered the question. LOL

I'm not sure I understand your response here. He gave you the correct answer (well almost ... After you average the 10 best from the last 20 differentials, you multiply the result by 0.96) so what is the "NO!!" For?? Edit: lol, apparently you edited your post between the time I read it and hit the quote button. Anyways, I believe he did correctly answer your question. :)

[BuckeyeNut]

I guess slope does count 621.5x 125 and 145..................got it!

[Golfingdad]

I guess slope does count 621.5x 125 and 145..................got it!

Correct. It's a smaller factor than cr, but it definitely matters. :)

[Fourputt]

I guess slope does count 621.5x 125 and 145..................got it!

This may be redundant, but here is the real poop, straight from the manual: USGA Handicap Calculation Formula

[BuckeyeNut]

All kidding and formulas aside....the CR is about 90-95% of what dictates the Index, and the slope is 100% of what decides the course HC.

[M2R]

I have a slightly different take on rating and slope relative to HCI. I'm not going to comment on course HC because that is a completely separate issue and quite frankly I know exactly the same as you, used in calculating CHC.  Between the two numbers the course rating is the only number of interest to the scratch golfer and the slope rating is the primary number of interest for a less skilled golfer (strictly in terms of HCI). I'll slightly modify your example to illustrate this using some mathematics.

For example......what if I score 75 on 2 courses......
75CR 125 slope
75CR 145 slope.......
Will the differential be different?

No exactly the same regardless of what slope rating is chosen in fact. The closer one gets to scratch the progressively less important slope is to the calculation, culminating in the ultimate case of being exactly scratch.

(75 - 75) * 113/125 = 0
(75 - 75) * 113/145 = 0

Changing the example again to illustrate the less skilled case.

For example......what if I score 105 on 2 courses......
75CR 125 slope
75CR 145 slope.......
Will the differential be different?

(105 - 75) * 113/125 = 27.1
(105 - 75) * 113/145 = 23.4

Very definitely yes, where the scratch player saw zero difference (differential) between the score he shot and the result adjusted by the formula, this player sees 3.7 strokes difference between courses and 6.6 strokes total difference from the actual score shot in the 145 slope case. To illustrate that 6.6 stroke difference I need to introduce another special case, the standard difficulty course.

For a slope of 113 players of all handicaps will find the course plays to exactly the same difficulty.

For example on a course rated 75 CR and 113 SR what are the differentials for scores of 75 and 105?

(75 - 75) * 113/113 = 0
(105 - 75) * 113/113 = 30, or (105 -75) * 1 = 30, and finally just (105 - 75) = 30

And in fact it is clear that the slope rating can be left out entirely, the differential is purely based on the score shot relative to the course rating.

In summary the closer to scratch the less important SR, the further from scratch the progressively more important SR becomes (strictly in terms of HCI calculations anyway). Everything in between is a sliding scale. The official statement on SR describes the same thing but for whatever reason I don't find it particularly clear, but it might make the light shine for someone else.

Quote:

A "Slope Rating" is the USGA's mark that indicates the measurement of the relative difficulty of a course for players who are not scratch golfers compared to the USGA Course Rating (e.g., compared to the difficulty of a course for scratch golfers).