Lydia Ko's Handicap +13? What?

[Golfingdad]

Just now, No Mulligans said:

 

Plus +8.5 as a woman and +4.0 as a man - still pretty darn badass all around.

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The thing to note about elite golfers, IMO, isn't so much their handicaps, it's their anti-handicaps.  If you take those 10 "bad" scores, her handicap goes up to only a +4.9.  Mine, OTOH, goes from 4.8 to over 10.

They're not just phenomenally good, they are consistently phenomenally good

[DeadMan]

Is that really how you do the bonus for excellence with plus handicaps? Your handicap actually goes up as a plus with the bonus for excellence?

[Lihu]

8 minutes ago, DeadMan said:

Is that really how you do the bonus for excellence with plus handicaps? Your handicap actually goes up as a plus with the bonus for excellence?

Seems like they should take that factor out for plus handicaps. They're by definition "excellent" already.

[No Mulligans]

7 minutes ago, Lihu said:

Seems like they should take that factor out for plus handicaps. They're by definition "excellent" already.

Yes, the slope calculation and the bonus for excellence don't make sense for the plus handicaps.

[MacDutch]

Think you should devide by .96 when handicap is +. 

[Big C]

41 minutes ago, MacDutch said:

Think you should devide by .96 when handicap is +. 

Well if the bonus for excellence is designed to tilt the scales in favor of the superior golfer, multiplying it makes sense. Dividing by .96 would hurt the "plus" golfer, while leaving the scratch golfer completely unaffected. So I think that part makes sense. 

What I don't understand is why the slope rating isn't modified or eliminated altogether for plus differentials.

[Golfingdad]

15 minutes ago, Big C said:

Well if the bonus for excellence is designed to tilt the scales in favor of the superior golfer, multiplying it makes sense.

Great point.  I guess it's the whole idea of par that throws us.  It's arbitrary and there is really no reason to cross over into negative numbers like that.  They could have just as easily made the formula something like "course rating is what a scratch golfer would shoot minus 15," or something like that, to keep everybody on the same side of the ledger and end the confusion.

[natureboy]

2 hours ago, Golfingdad said:

Great point.  I guess it's the whole idea of par that throws us.  It's arbitrary and there is really no reason to cross over into negative numbers like that.  They could have just as easily made the formula something like "course rating is what a scratch golfer would shoot minus 15," or something like that, to keep everybody on the same side of the ledger and end the confusion.

I just looked at that and increasing the total amount that you multiply by .96 shifts the expected average score for everyone by a couple of strokes, and moves zero handicap off par for 'typical' courses.

Eliminating the .96 factor makes the 72 CR / 100 slope issue go away, while zero HCP remains right around 72 on a typical course. It does make the average score on the PGA roughly equivalent to a plus six, which may be accurate, but I thought the average tour pro (~90th scoring rank) was more like a 4-5?

They may have already looked at the calculation issue and figured the high course rating low slope scenario was so rare that it didn't need to upset the apple cart for the bulk of golfers at higher handicaps (for whom slope is primarily intended). I expect most plus players play to par and not net, though the lesser golfer would be wise not to put money on the game.

Edited May 10, 2016 by natureboy

[SavvySwede]

16 minutes ago, natureboy said:

I just looked at that and increasing the total amount that you multiply by .96 shifts the expected average score for everyone by a couple  of strokes, and moves zero handicap off par for 'typical' courses. Eliminating the .96 factor makes the 72 CR / 100 slope issue go away, while zero HCP remains right around 72 on a typical course. It does make the average score on the PGA roughly equivalent to a plus six, which may be accurate, but I thought the average tour pro (~90th scoring rank) was more like a 4-5?

They may have already looked at the calculation issue and figured the high course rating low slope scenario was so rare that it didn't need to upset the apple cart for the bulk of golfers at higher handicaps (for whom slope is primarily intended). I expect most plus players play to par and not net, though the lesser golfer would be wise not to put money on the game.

The PGA guys are really tough to figure because you don't have course ratings for the type of conditions they're playing in. Oakmont is 77.5/147 from the tips but come the U.S Open who knows what it is actually playing at?

[natureboy]

26 minutes ago, SavvySwede said:

The PGA guys are really tough to figure because you don't have course ratings for the type of conditions they're playing in. Oakmont is 77.5/147 from the tips but come the U.S Open who knows what it is actually playing at?

Fair point on the majors, but I think for a rota of regular tour events that the approximate rating and slope for the championship tees is likely pretty close. Besides the setup a significant part of the difficulty will be the conversion of the par for what's normally a par 5.

Edited May 10, 2016 by natureboy

[Golfingdad]

51 minutes ago, natureboy said:

I just looked at that and increasing the total amount that you multiply by .96 shifts the expected average score for everyone by a couple of strokes, and moves zero handicap off par for 'typical' courses.

Eliminating the .96 factor makes the 72 CR / 100 slope issue go away, while zero HCP remains right around 72 on a typical course. It does make the average score on the PGA roughly equivalent to a plus six, which may be accurate, but I thought the average tour pro (~90th scoring rank) was more like a 4-5?

They may have already looked at the calculation issue and figured the high course rating low slope scenario was so rare that it didn't need to upset the apple cart for the bulk of golfers at higher handicaps (for whom slope is primarily intended). I expect most plus players play to par and not net, though the lesser golfer would be wise not to put money on the game.

Then I would suggest we do what @No Mulligans said ... Subtract the 15 (or  10 or whatever) from the rating to be able to do all of the math on the same side of zero, but then add it back in afterwards to normalize the caps back to what we're used to.

Would that work?

Note that my interest in this is purely mathematical at this point - practically I've concluded that it just really doesn't matter. :P

[natureboy]

1 minute ago, Golfingdad said:

Then I would suggest we do what @No Mulligans said ... Subtract the 15 (or  10 or whatever) from the rating to be able to do all of the math on the same side of zero, but then add it back in afterwards to normalize the caps back to what we're used to.

Would that work? Note that my interest in this is purely mathematical at this point - practically I've concluded that it just really doesn't matter. :P

I was kind of responding to both points. It looks like it won't really work because of the .96 multiplier. If that's eliminated then scratch will stay put and scores line up pretty good with relatively minor shifts for the other HCPs on the really tough courses. If you don't multiply the 15 or 13 by the .96 or the divisor it's the same as adding zero to the result.

To my eye the results with no .96 look pretty accurate. Zero HCP plays to an average of 72 on CR 72 / slope 113 and only slightly above for CR 72 / slope 120. A 6 HCP would average about 66.5 on CR 72 / slope 120 and about 71 on 75/140. I think the latter makes sense, because most of us build HCPs on a familiar course or two, whereas when calculate HCPs from pro tournament scores they are on courses not as familiar, while their home course HCPs seem to be a bit higher than you'd calculate from their tournament scores.

 

[Mr22putt]

On 5/9/2016 at 0:14 PM, Big C said:

I'm pretty sure the math is incorrect. For example, the 64 she shot at Wildfire Golf Club would convert to a -11.5 differential, not -15.1 as you have listed it.

It's the opposite of the way that most golfers intuitively think the system should work, but I suppose the USGA figures it effects so few golfers that they don't care to correct it. 

.

 

Ya...I'd say -15.1 makes more sense than -11.5...but we know this is wrong.

Yes....your view that the USGA can't be bothered to tweak it.....based on it affects few golfers makes sense.

Many pro golfers don't carry an official handicap....I think women pro golfer's s/b based on a men's handicap if any analysis is done....like the one in this thread.

Let's also not forget that....many times...the LPGA plays their events....100-200 yards shorter than what is posted on the lpga.com site....which would affect course rating and slope.

No question that Lydia is +3 to +5 handicap based on a men's rating scale.

Edited May 12, 2016 by Mr22putt

[gregsandiego]

On 5/9/2016 at 11:49 AM, No Mulligans said:

I took a swag at calculating Lydia Ko's Handicap based on the last 20 tournament rounds that she had.  I got +12.9.  What?

Did I do this right?

 

Why does calculating the handicap seem like  such an arcane algorithm.

 

Edited May 12, 2016 by gregsandiego
typo

[natureboy]

Now they don't do strokes gained on the LPGA, but I took a crack at hacking a 'backdoor' approach to get a similar type evaluation of their games.

Basically I looked at the standard deviations above and below the average for driving distance, fairway%, GIR%, and PPGIR. GIR is a combination of driving and approach skill so if you gained as many standard deviations on the drive as you lost on approach you'd have an average GIR%. Now strokes gained actually weights different shots differently, but this is an estimate to compare relative skills. You can do the same with PPGIR. If your GIR% is well above the average, then you should make more putts (if you at least an average putter), because (on average) your better GIR% reflects better proximity to the hole.

Turns out that 2015 Lydia was a slighty better than average driver (mostly owing to her accuracy). She is an average putter, but was the best approach player...so much so that she ended up 2nd in ballstriking. Lexi was #1 in driving and 7th in approach play so she was 1st in ballstriking. But she is near last in PPGIR relative to her GIR so that's why she doesn't win as frequently as Lydia despite slightly edging Lydia in ballstriking skill relative to the tour average.