Ratings and slope - Analysis of over 3000 tournament rounds

[Cklguy2013]

Hey guys with a view to improving upon the current rating system for courses I analyzed over 3,000 tournament rounds, and found some interesting results. For the time being here is an overview of the scoring,

Rounds, 3012, Median score - 81, rounds in the 60s - 83, 70s - 1145, 80s - 1136, 90s - 451 and over 100 - 197.

Next post I'll share some thoughts on how courses should be rated based upon my findings.

[Cklguy2013]

Data on course that have been played multiple times, with many rounds. (Top 5% Yards = yards divided/( by top five scoring average -36 putts))

					Scoring	Scoring		Top 5%
	Yards	Par	Rounds	Best	Top 10%	Top 5%	Median	Yards
Congressional CC (Protee)	6,462	71	170	63	68.9	67.6	82.0	204
TPC @ Boston (Protee)	6,380	72	126	66	68.6	68.0	80.0	199
Oceanic Athletic Club	6,777	72	170	68	71.0	70.3	82.0	198
Magnolia National 2016 (Protee)	6,356	72	190	65	70.5	68.6	80.0	195
NGLA - The National (ProTee)	6,514	72	180	67	70.2	68.8	80.0	199
Stonebirdge GC - Ottawa (Black - A - ProTee)	6,451	73	163	67	69.3	68.4	78.0	199
Average	6,490	72	167		69.8	68.6	80.3	199.0

[aja]

From a statistics viewpoint, the sample of tournament rounds does not really represent all of the rounds of golf played, those which are played outside of tournaments. As well the tournament rounds suffer from a bit of bias since not all players participate at equal rates.

I play the tournaments but relatively infrequently. That means my rounds (and poor scores), which are usually in the 90 - 100 range will be underrepresented.

I suspect that the golfers who shoot better scores tend to have higher participation rates in the tournaments so their (better) scores would tend to skew the results.

Just my 2 cents, for what it's worth.

[Cklguy2013]

No question not perfect, but what I'm driving at in the previous post is what does a scratch golfer score, and what similarities do we see course to course? I've arbitrarily defined "scratch golfer" as "top 5% scores", honestly I think this should even be lower, say 2%, but based on a lack of data points one low score can skew the number too much if we only use only 2%.

[aja]

Ratings and Slope are two different measures as you are aware. The Rating is determined from (and applies) to "par" golfers (maybe your 5% - 2%). However, the Slope applies to "bogey" golfers, so that's a different group entirely.

[Cklguy2013]

Yes I do realize that, but first you have to determine a course rating for a scratch golfer,then you determine it for a bogey golfer, and the difference multiplied by 5.38 give you slope, but first we need the "scratch rating", and no worries, I have thoughts on how to slope as well, but I want some discussion of rating first.

Also, keep in mind we currently seem to be using par as the rating, which obviously has its limitations.

[Wyzyguy]

Hello CKL... Where did you get your data? It would be interesting to know the average (Mean) and what the standard deviation would be. That would tell you the approx range of scores for approx 70% of rounds play in comparison to the 5% & 10%. The Top 5% yardage stat is an interesting one.A strokes gain figure would be cool as well.

[Cklguy2013]

Pulled it from the tournament site into exel.

[wbond]

What does this equation tell you?

(Top 5% Yards = yards divided/( by top five scoring average -36))

[Cklguy2013]

Basically it's showing a proxy for determining a rating based on yardage. If you used 200 yard per stroke for example a 6,000 yard course would be rated at 66 (6000/200+36), whereas a 7000 yard course would be rated at 71 (7000/200+36). I would say this would be your starting point for a rating then adjusted up or down for effective yardage and obstacles. Not perfect but much better than using par where they might both be rated the same using par of 72 say. Also, I'll spare you the details but in looking at the 3,012 scores it is clear as yardage goes up scores increase, even for the very best players.

[Wyzyguy]

Looks to me like the net gain in yards per full shot in top 5% scores assuming 36 putts per round. Top 5% players are gaining approx 200 yards per full shot vs approx 150 yards per full shot for an 80 shooter under the same measure. I could be completely wrong though.

[Cklguy2013]

See above.

[Wyzyguy]

Doing some really suspect math on the numbers above I a have a WAG of an average score @ 83.5 (MEAN) and a standard deviation of about 13... So... With bad math and poor guess I am thinking about 70% of the scores fall between 70.5 and 96.5 (+/-).. What is this good for? Not sure but it was fun.

[Cklguy2013]

What I'm trying to drive at here is more rating i.e. the score of a scratch player.

But, fyi on the full 3,012 scores for all courses, 50 % of all scores fall between 77 and 88, 60% between 76 and 90, 70% fall between 74 and 93, 80% between 73 and 96, 90% between 71 and 102, with a mean of 81.

[Cklguy2013]

This seems to have fallen on deaf ears. Bottom line is that par is a very poor measure of course rating. Ratings could easily be based on yardage, which would be easy to implement and, although not perfect, be a big improvement.

[ProTee United]

This is really complex stuff, so I'm not surprised about the lack of response. We can change the course ratings for tournaments.

This is how its being calculated in TGC (not used in our tournaments): http://thegolfclubgame.com/2015/03/3...slope-ratings/

Aja is right about the different type of course play outside tournaments, so we need to use the tournament historic data only.

[Godfather]

This is really complex stuff, so I'm not surprised about the lack of response. We can change the course ratings for tournaments.

This is how its being calculated in TGC (not used in our tournaments): http://thegolfclubgame.com/2015/03/3...slope-ratings/

Aja is right about the different type of course play outside tournaments, so we need to use the tournament historic data only.

Great info. I'd thought of running some regression analysis (and perhaps neural network analysis) on the data with controlling for the player and course. Sometimes, though, the simplest solution is the best and plotting score relative to par against handicap is pretty good even if the handicap refers back to how the past courses were rated so it would have to be adjusted over time.

This seems like a good idea to implement for sim tournaments going forward as it should bring hazards, green difficulty into play in addition to effective length.

[mthunt]

I think it's fallen on deaf ears because the current system is working. Why is the change being proposed? Are there examples of players winning or finishing high due to a bad handicap (other than a new player)?

[mthunt]

I hear you but I don't see it as a necessary change. There are more important things to focus on. Stay tuned for further refinements to improve the sim experience.

[Cklguy2013]

Do you run the forum mthunt? Just wanting to know who I'm speaking with. So your decisions are final?

[mthunt]

Keither50 and myself are the TGC tour commissioners. I have nothing to do with the forum and I don't own ProTee or the forum. Is MY decision final? No.

[wbond]

At the end of the day, is it going to change/improve anything? Now that everyone is being measured to the same system, I don't know that this would do anything different other than output a different number for each player. I think they would still be in the same position relative to other players.

[wbond]

So are we talking about drives now or HDCP. I have no idea why anyone would jack up driver or any club, makes zero sense. As far as realistic, please stop. 6' gimmies, no sand, no rough, no wind, no affect on lie, guessing break on a video game. My point was we now have a system that everyone is measured against, this was a huge improvement over someone arbitrarily changing HDCP's which is what appeared to be going on. If this is an easy fix and provides a definitive improvement, then my guess is they will do it. I was questioning whether your proposed method is going to actually change the output in relation to player vs player. If it just slides everyone's hdcp in a particular direction, what was accomplished?

[mthunt]

Dude, your best on grass is 5 shots higher than your best on fake grass. I don't get it. I shot in the 60's for like 5 tournament rounds in row. I don't do that outside. I'm sure how playing with boost is the same.

[Cklguy2013]

And your point is what? I don't understand why this is such a difficult concept to grasp. Of course sim scores and real life scores are different, but handicaps don't have to be if course ratings are lower on here Dude.

[andygg1986]

The way that this could make a difference is if someone decided to only play hard or easy courses for a while and then played one of the other type. Here are a couple other ways of looking at it. Cklguy course rating = yards/199 + 36

top 5% vs par top 5% vs Cklguy course rating median vs par median vs Cklguy course rating
Congressional -3.4 -0.9 +11 +13.5
TPC Boston -4.0 -0.1 +8 +11.9
Oceanic Athletic Club -1.7 +0.2 +10 +11.9
Magnolia -3.4 +0.7 +8 +12.1
NGLA -3.2 +0.1 +8 +11.3
Stonebridge -4.6 +0 +5 +9.6

Variation 2.9 1.6 6 3.9
Average -3.4 0 8.3 +11.7

So using Cklguy's rating method, there would be less variation in net scores between easy and hard courses for both top 5% and median golfers, and overall everyone would have a handicap that is 3.4 points higher if they played every tournament.

I think the key point though is that most people play the majority of tournaments, so as long as it is the same for everyone it won't really matter. The beginner learning curve will have a much bigger impact on initial handicaps than the couple of points that could happen depending on which tournament you play.

[Cklguy2013]

I agree I would see handicaps going up in the range of 4.

Why wouldnt people want more realistic handicaps especially if it's an easy fix?

Its not not about gaining or losing a competitive advantage, it's about improving realism as we all do with our sims, distance, ball speed, etc.

[Cklguy2013]

Wbond,

do do you want a handicap on here that relates to a real life handicap? Yes or no?