Slope Ratings

[Peter Pallotta]

That's interesting/instructive: Crystal Downs is the easiest 140 I've ever played!
Actually, the better word is the 'friendliest' -- it was by far the friendliest course with that high a slope rating I ever played.
I didn't score very well at all, at least 10 strokes over my 'handicap'/expected score. But it felt like the golf course wasn't the cause of this, and wasn't to blame.
It was giving me every chance to do okay, and wasn't mean or pernicious in the least.
But then again, maybe 'friendly' isn't the right word either.
It was the most 'duplicitous' 140 I've ever played: a 140 masquerading as a 130 -- the proverbial wolf in sheep's clothing!

[Bob Harris]

A so-called 113 slope average course is certainly not an "average" type of course in any of the areas that I have ever lived in.

The USGA says "A course of standard difficulty has a Slope Rating of 113."

That is different than "an average course" or even a typical course. It's a course of "standard difficulty."

Jeff, yeah, we're constantly calibrating ourselves against others.

From Dean Knuth's website: written in 2008


When I introduced the system in 1982, the theoretical average Slope Rating was 113 because USGA data showed that scores go up on average 1.13 strokes per handicap stroke. The actual average Slope Rating is 120. The majority of courses in coastal states have Slopes of 121 and higher. Many Slopes lower than 118 are mid-American public courses.

[Erik J. Barzeski]

From Dean Knuth's website: written in 2008

When I introduced the system in 1982, the theoretical average Slope Rating was 113 because USGA data showed that scores go up on average 1.13 strokes per handicap stroke. The actual average Slope Rating is 120. The majority of courses in coastal states have Slopes of 121 and higher. Many Slopes lower than 118 are mid-American public courses.

Thanks for the insight. I think the average might be 121 or 122 these days, but yeah, you can look up on the USGA's site how they talk about the 113 as the "standard difficulty" these days.

[Michael Whitaker]

Tom - I don’t think your theory is valid because rating teams do not compare their results to other course before submitting them... at least that is my understanding from the team members I have talked with. They take their measurements, complete their evaluations, and submit their data. The results are just a calculation of the raw input. If you are suggesting that the raters compare the outcome to other courses and then somehow “tweak” the result to make it fall into a predetermined scale is a bit far fetched, IMO. I don’t really think there is a conspiracy at work here. 🥴


As to your thoughts on different states having their own scales... all teams follow specific guidelines for executing a rating and it is very objective, with hard instructions for determining the raw data. You make it sound like the teams can change the data collection procedure as they see fit. They can’t. It’s a fixed process based on physical measurements. 200 yards in South Carolina is 200 yds in Michigan.

[Erik J. Barzeski]

Tom - I don’t think your theory is valid because rating teams do not compare their results to other course before submitting them... at least that is my understanding from the team members I have talked with. They take their measurements, complete their evaluations, and submit their data. The results are just a calculation of the raw input. If you are suggesting that the raters compare the outcome to other courses and then somehow “tweak” the result to make it fall into a predetermined scale is a bit far fetched, IMO. I don’t really think there is a conspiracy at work here. 🥴

As to your thoughts on different states having their own scales... all teams follow specific guidelines for executing a rating and it is very objective, with hard instructions for determining the raw data. You make it sound like the teams can change the data collection procedure as they see fit. They can’t. It’s a fixed process based on physical measurements. 200 yards in South Carolina is 200 yds in Michigan.

Like or +1. 

[Michael Whitaker]

200 yards in South Carolina is 200 yds in Michigan.

You know, now that I think about it, I might be wrong about this. We are a little slow here in South Carolina. 200 yds in Michigan might only be worth 180 in SC.   

[Joe Zucker]

Are there any adjustments for standard weather?  For example, living in the PNW for a few years the ball doesn't fly as far.  Then moving to Texas where it is always hot, I picked up at least one club of distance.  On a "normal" day, an identical course would be easier in TX than Seattle.  I'm guessing that's not factored in, but curious?


Another pet peeve of mine in Seattle was that many courses had pine trees with limbs all the way down to the ground.  So recoveries were difficult or impossible.  Does the slope rating account for the type of tree or just the width of the playing corridor?  Because I felt that made a difference.

[Bob Harris]

Are there any adjustments for standard weather?  For example, living in the PNW for a few years the ball doesn't fly as far.  Then moving to Texas where it is always hot, I picked up at least one club of distance.  On a "normal" day, an identical course would be easier in TX than Seattle.  I'm guessing that's not factored in, but curious?


Another pet peeve of mine in Seattle was that many courses had pine trees with limbs all the way down to the ground.  So recoveries were difficult or impossible.  Does the slope rating account for the type of tree or just the width of the playing corridor?  Because I felt that made a difference.

There are adjustments for elevation, wind and altitude. The Playing Condition Calculation would apply if the course or weather conditions on a day impacts scores. 


In regard to trees, the ability to recover (low hanging limbs, roots, mulch) is considered in calculating course rating and slope.

[Tom_Doak]

Tom - I don’t think your theory is valid because rating teams do not compare their results to other course before submitting them... at least that is my understanding from the team members I have talked with. They take their measurements, complete their evaluations, and submit their data. The results are just a calculation of the raw input. If you are suggesting that the raters compare the outcome to other courses and then somehow “tweak” the result to make it fall into a predetermined scale is a bit far fetched, IMO. I don’t really think there is a conspiracy at work here. 🥴


As to your thoughts on different states having their own scales... all teams follow specific guidelines for executing a rating and it is very objective, with hard instructions for determining the raw data. You make it sound like the teams can change the data collection procedure as they see fit. They can’t. It’s a fixed process based on physical measurements. 200 yards in South Carolina is 200 yds in Michigan.

Michael:


When the Old course at Stonewall opened, the GAP rating team came out and gave it a slope of 128 or some such.  The founders howled in protest, suggested it was a much tougher scoring course than others locally that had higher slopes, and asked for it to be re-rated.  It's now at 136, with three or four back tees that weren't there originally.


I wasn't suggesting that the rating team got together after the round to make the order "feel right", but that the golf associations do so, over time and re-ratings.

[Michael Whitaker]

...with three or four back tees that weren't there originally.

Understandable. That's what back tees do to the numbers.


If those tees had been there originally the course would have gotten that slope rating the first time around.

[Ed Brzezowski]

Tom - I don’t think your theory is valid because rating teams do not compare their results to other course before submitting them... at least that is my understanding from the team members I have talked with. They take their measurements, complete their evaluations, and submit their data. The results are just a calculation of the raw input. If you are suggesting that the raters compare the outcome to other courses and then somehow “tweak” the result to make it fall into a predetermined scale is a bit far fetched, IMO. I don’t really think there is a conspiracy at work here. 🥴


As to your thoughts on different states having their own scales... all teams follow specific guidelines for executing a rating and it is very objective, with hard instructions for determining the raw data. You make it sound like the teams can change the data collection procedure as they see fit. They can’t. It’s a fixed process based on physical measurements. 200 yards in South Carolina is 200 yds in Michigan.

Michael:


When the Old course at Stonewall opened, the GAP rating team came out and gave it a slope of 128 or some such.  The founders howled in protest, suggested it was a much tougher scoring course than others locally that had higher slopes, and asked for it to be re-rated.  It's now at 136, with three or four back tees that weren't there originally.


I wasn't suggesting that the rating team got together after the round to make the order "feel right", but that the golf associations do so, over time and re-ratings.




Of course we do, things change over time. A few years ago you could lose a short golfer in the fescue right of eight. Now you have a chance of advancing the ball. Trees have grown and now intrude a bit more. green sizes seem to change. As you know it's a living thing that evolves, so do the ratings.

[Erik J. Barzeski]

Does the slope rating account for the type of tree or just the width of the playing corridor?

Yes.

And there are adjustments for weather, prevailing wind, etc. too. Like most adjustments, they're small, as distance is the dominant factor in course ratings.

Understandable. That's what back tees do to the numbers.If those tees had been there originally the course would have gotten that slope rating the first time around.

+1

[Garland Bayley]

Would be interested in you guys commenting on this:   At my course in the northeast, the membership strongly believes the course rating and slope of 72/136 for our par 71 course is too high from the middle tees (6500 or so) and the back tees (6800, rated 73.3/138......as compared to Florida courses that some of us play, with water running the length of most holes on one side or the other.   The Florida courses tend to be par 72, rated 71, slope 130ish.  So there’s a couple stroke difference just in rating, then add in slope.   But the difference to us seems to be backward!  We all feel Florida is much more difficult just because of the water? Our scoring backs that view up.


At my northeastern course, I can slice or hook it into an adjoining fairway, and still have a shot at par, maybe birdie, depending on trees and such.   Do that in Florida, and you just made double or triple, and you have not left the tee box yet.   How to reconcile this?    I am a 5.2 index in the NE.   When I go to fla, my index jumps by 5 or more strokes over 30 rounds. The same is true of every single person in my group.  Something is screwy?

You sound like you and you buddies are wild Willys (Dean Knuth's term) like my buddies and me. We don't fit the averages that go into making statistical handicap systems. If I remember correctly, there is a group of short straight hitters that also don't fit handicap statistics that slightly outnumber us. In Florida, they would empty your wallet in a hurry, whereas at your home course you would be emptying theirs.

[Tom_Doak]

Of course we do, things change over time. A few years ago you could lose a short golfer in the fescue right of eight. Now you have a chance of advancing the ball. Trees have grown and now intrude a bit more. green sizes seem to change. As you know it's a living thing that evolves, so do the ratings.

Ed:


Yeah, the rough used to be TOUGHER on eight, but the Slope rating is higher NOW.


I guess the greens are faster.  But I do think there is inevitably a bunch of jiggling done based on local comparisons.  And as noted earlier, comparisons from state to state make less sense.

[Bob Harris]

Of course we do, things change over time. A few years ago you could lose a short golfer in the fescue right of eight. Now you have a chance of advancing the ball. Trees have grown and now intrude a bit more. green sizes seem to change. As you know it's a living thing that evolves, so do the ratings.

Ed:


Yeah, the rough used to be TOUGHER on eight, but the Slope rating is higher NOW.


I guess the greens are faster.  But I do think there is inevitably a bunch of jiggling done based on local comparisons.  And as noted earlier, comparisons from state to state make less sense.

There was no jiggling.  The effective playing length has increased by 100 yards for the middle tees and 147 yards for the back tees.  That and the increase in green speed would account for the increases in the course rating/slope.

[Mark_Fine]

Lots of good information in this thread.  Thanks.  I still don’t know if any of it changed my mind about how I feel about slope ratings.  Honestly I put more credence in the course rating vs the slope rating for most courses.  I realize neither are perfect sciences but slope ratings for whatever reason seem all over the map to me.


Note:  I just played in a Philly GAP tournament today.  The slope rating was 132.  Sorry but no way that was right compared to other 132’s I have played recently including my home club. Whatever 

[Ed Brzezowski]

Of course we do, things change over time. A few years ago you could lose a short golfer in the fescue right of eight. Now you have a chance of advancing the ball. Trees have grown and now intrude a bit more. green sizes seem to change. As you know it's a living thing that evolves, so do the ratings.

Ed:


Yeah, the rough used to be TOUGHER on eight, but the Slope rating is higher NOW.


I guess the greens are faster.  But I do think there is inevitably a bunch of jiggling done based on local comparisons.  And as noted earlier, comparisons from state to state make less sense.

There was no jiggling.  The effective playing length has increased by 100 yards for the middle tees and 147 yards for the back tees.  That and the increase in green speed would account for the increases in the course rating/slope.

Well Tom I did the last rating at Stonewall and i'm with Bob. There were no shinnanigans. Course was longer, some landing areas are narrower and some  areas of extreme rough  did grow up considerably. Honestly I think the  normal rough was a bit longer too. Yes eight was more playable but the bogey golfer is in trouble in that fescue. Dude it's a hard course and it's maturing into a harder one.  ed

[David Royer]

I'm a rater for the OGA.  I'm relatively new to the process.  With the new manual out this year the process is very objective.  95% length. I think the hardest thing for most golfers is to understand the factors between scratch and bogey distance and how it affects slope or doesn't.  We never discuss the rating forms with the club.   I encourage people to become raters with their association. You visit courses you probably either don't know about or play.  It's a great way to see some architecture that sometimes goes unappreciated. (On both ends of the spectrum)

[Jerry Kluger]

How much does out of bounds and water hazards affect course rating?

[Michael Whitaker]

I'm a rater for the OGA.  I'm relatively new to the process.  With the new manual out this year the process is very objective.  95% length. I think the hardest thing for most golfers is to understand the factors between scratch and bogey distance and how it affects slope or doesn't.  We never discuss the rating forms with the club.   I encourage people to become raters with their association. You visit courses you probably either don't know about or play.  It's a great way to see some architecture that sometimes goes unappreciated. (On both ends of the spectrum)

+1

[David Royer]

" Crossing Obstacles consist of penalty areas, extreme rough, and OB."  Ratings are based on length of carry to safely cross. Depending on length a scratch player can have a value ranging from Plus 1 to plus 5 100-230 yards. Bogey is 50-180.water in front of green is generally a plus 1 factor.  Lateral obstacles are the same but "laterally".  Factors are location, size, conditions.  Squeeze can be a factor between two laterals.  Helpful?

[Tommy Williamsen]

Iwonder how much familiarity impacts slope. From the tees I play my course is sloped at 145. For first time players the course can be terrifying. After a few plays we discover how to play the course without to many disasters. I spent four days at Victoria National last year. The first time around I thought it was sloped too low. After a few plays I knew where to hit the ball. Course raters see it one time. I'm not sure once is truly enough to do an accurate rating.

[Mark Pearce]

This thread makes me so excited to see the OWGH system start up in the UK.

[JohnVDB]

When the Old course at Stonewall opened, the GAP rating team came out and gave it a slope of 128 or some such.  The founders howled in protest, suggested it was a much tougher scoring course than others locally that had higher slopes, and asked for it to be re-rated.  It's now at 136, with three or four back tees that weren't there originally.

I rated about 150 courses in Oregon and Western PA over the years and am hoping to get back into it next year in NJ.
The funny thing about that is when if either the course rating or the slope increase your handicap will go down.  If you average 80 on a course with a 70.0 rating and 128 slope, you are not as good a player as if you average 80 on a 71.0/136 course.
I can't tell you how many times I showed up at a course and had a member there tell me how his course is a lot tougher than the rating shows.  I then explain that to him and he immediately wants the ratings lowered so his handicap will go up.
You cannot judge the difficulty of a course just from the slope and to do so is a big mistake.
As Michael pointed out, the slope is just the slope of the line of the difference between the course rating and the bogey rating. As an example working the formula backwards to get the Bogey Rating from the Royal Dornoch scorecard:
Yellow Tees: Rating 71.1, Slope 129 yields a Bogey Rating of 95.1White Tees: Rating 72.6, Slope 134 yields a Bogey Rating of 97.5
So, while the Scratch Course Rating goes up 1.5 strokes from the Yellow to the White, the Bogey Rating goes up 2.4 strokes that .9 difference changes the slope from 129 to 134. 

I'll note that while it is extremely rare, it is possible for the longer tees to have a lower slope than the shorter ones.  This happens occasionally when the bogey golf might not be forced to layup from the longer tees or might have most of the greens just beyond the length he can reach in regulation from those tees whereas he could reach them from the shorter tees with a much longer shot.

As others have said, the Effective Playing Length (yardage plus things like wind, elevation change etc) of each hole makes up 90-95% of the Scratch and Bogey Ratings. Of the remaining 5-10%, most of that comes directly from measurements and tables and is not subjective.  The actual amount the rating team can subjectively determine is very small.

[Garland Bayley]

... With the new manual out this year the process is very objective.  95% length. ...

The manual doesn't really say that does it? If it does, then something is very wrong with some ratings, or with that statement.

I have been looking at some ratings on line i use the GHIN app to get the latest ratings, and i look up score cards online. Many of the scorecards are out of date, and show significant changes in slope ratings without any changes in length that i am aware of.

For example, Club Green Meadows in Vancouver, Washington. Golflink has it at 72 par | 6,486 yards | 118 slope, but the GHIN app has it at 132 slope. So a 12% change in slope rating without a change in length.