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Par Talk

Which of these best describes Hole 18 at the Utah Open?

  • A par 2 where 38% of throws are errors, and 1% of throws are hero throws.

    Votes: 6 25.0%

  • A par 3 where 24% of throws are errors, and 33% of throws are hero throws.

    Votes: 16 66.7%

  • A par 4 where 16% of throws are hero throws, and 23% are double heroes.

    Votes: 1 4.2%

  • A par 5 where 37% of throws are hero throws, and 21% are double heroes.

    Votes: 0 0.0%

  • A par 6 where 16% of throws are hero throws, and 62% are double heroes.

    Votes: 1 4.2%
  • Total voters
    24
  • Poll closed .
roblee said:
A couple take aways for me:
1. The data support conventional thinking.
2. The criteria for defining disc golf par are different than for golf par.
Click to expand...
2. At the most fundamental level (the definitions) they are based on exactly the same principle. Essentially, the score expected of an expert.

Methods and parameters are different between the sports. As the paper shows, one parameter that does not carry over is the expected number of putts. (Duh!) The paper also shows that relying on a tight relationship between length and score doesn't work as well for disc golf. Even when you account for the much shorter drives in disc golf.
 
I played an event yesterday with some real live Par 2's. Shot the 2 lowest round scores of my PDGA career and won it as well- yay me! My feeling from looking at and playing the holes is there were 13-14 Par 2's along with 4-5 easy Par 3's. My 29 under for the day becomes right around even par. Curious to see what the Steve West Par-a-nator spits out. Possible par 3's imo in descending order of difficulty- 8,7,3, 17,14. (I did ace 14 though.) I have intentionally not looked at the hole scores to this point. Small samples with a lot of players spread out over a wide range of ratings with no players above 930 or so.

Merry has Little Lambs
 
biscoe said:
I played an event yesterday with some real live Par 2's. Shot the 2 lowest round scores of my PDGA career and won it as well- yay me! My feeling from looking at and playing the holes is there were 13-14 Par 2's along with 4-5 easy Par 3's. My 29 under for the day becomes right around even par. Curious to see what the Steve West Par-a-nator spits out. Possible par 3's imo in descending order of difficulty- 8,7,3, 17,14. (I did ace 14 though.) I have intentionally not looked at the hole scores to this point. Small samples with a lot of players spread out over a wide range of ratings with no players above 930 or so.

Merry has Little Lambs
Click to expand...
We could discuss whether MPO should have been playing this short of a course at all. But, let's set that aside and look at how the methods in the PDGA Par Guidelines work.

Biscoe gave us the results of the "Par by Expert Opinion" method; total par of 40 or 41 with holes #8, #7, #3, #14, and maybe #17 as par 3.

The "Par Adjusted by Round Ratings" method says an even-par round should usually be rated between 990 and 1030, depending on how much punishment the course doles out. To get to am average round rating of 990 over both rounds, we would need to go down to par of 39. The five hardest holes by field average are #7, #8, #3, #17, and #14. So, we could set par to 39 (=990 rated) by saying #7, #8, and #3 are par 3s (and the rest par 2s). If there is very little punishment on this course (Which I think is likely, because where could you fit it?), we could include hole #17 for a 974-rated par of 40.

I think a 956-rated par of 41 would be pushing it. Would any 1000-rated player feel their 956-rated round was what they would expect with errorless play? Or would they be able to tell you where they left one or two throws out there?

The "Par by Hole Length" method shows that at about 185 feet, a hole has a 50/50 chance of being a par 3 or a par 2. For more detail, the "Par by Hole Length and Hole Difficulty" shows that the six holes in the 160-180 foot range could each have a good chance of being par 3. I don't have the knowledge of the holes that would be needed to make that call.

The "Close Range Par" method would put all the holes within Close Range (thus, par 2s), but only if there were no elevation or doglegs.

The "Par by Effective Hole Length and Foliage" would call all the holes par 2 if they have light foliage, but the 160+ foot holes could be par 3s if they have heavy foliage.

For the Score-based methods, we have to extrapolate because there were no 1000-rated players. With this extrapolation, both the "Par by Average Score" method and the "Par by Scoring Distribution" method would give only holes #7, #3, and #8 an MPO par of 3. Both methods rank #13 as next most difficult, followed by #14 and #17.

Which all goes to show that the TD always needs to make the final call. I personally would set par for MPO at 39, with par 3 for the three holes Biscoe picked as the most difficult.
 
I'm thinking about a possible refinement to my formula for setting par by scores.

I'm satisfied that my current method will not set a par that is too low. (It sets par so that every throw has at least a 76.7% chance of leading to a par score.)

Now, I'm considering something to make sure it does not set par too high. Here is what's happening.

TDs and course designers are finding ways to get more scoring separation. This presents a challenge to any method for setting par. The more the scores are smeared out, the less obvious which score is the "expected" one.

For example, say the "expert" on the hole gets a scoring distribution of 20%x2, 20%x3, 20%x4,20%x5, 20%x6. Per my method, this would be par 4 because only 73.6% of throws contribute to a score of 3 or better.

73.6% = (20%+20%)^(1/3)

The average is also exactly 4. So far, so good.

Here's the problem. There shouldn't be that many eagles. To get an eagle, a player needs to make one throw that does the work of three throws. Or, make two throws that do the work of four throws.

As an example, a 1000-rated MPO player can get par with 427-foot drives, so an eagle that results from good drives would require one 1281-foot drive, or two 854-foot drives, or three 711-foot drives. Not impossible (especially for a player rated higher than the 1000-rated "expert") but it should not happen 20% of the time by players at exactly the skill level of an expert.

The holes where I'm seeing these spread-out distributions seem to be water carries. Maybe some artificial islands.

Making the water carry and gaining two throws on the other experts doesn't mean the players who cleared the water beat "errorless play" by two throws, it means that a lot of experts are making the two-throw error of throwing into the lake.

What I'm thinking is that there might be some cap on eagles. To me, 20% eagles is too many. In the 20/20/20/20/20 example, this rule would kick in and set par to 3. If 40% are getting 3 or better, and half of those players are getting 2, is anyone going to think that the scores of 4 do not include an error?

Thresholds for low percentages are tricky. Maybe it shouldn't be a flat percentage, but a count of the actual number of eagles. For example, I could see ignoring one eagle from the experts, even if there were only 5 experts.

Or maybe we could look for a way to identify the scores that resulted from two-throw errors and discount that effect somehow.

Your thoughts?
 
The difficulty of determining par by an errorless rate on each throw, is that all errors are not created equal.

Some errors give the thrower a reasonable chance at a save, with not just an average subsequent throw, but an above-average subsequent throw. Some give a slight chance of a save, with a great subsequent throw. Some, particularly water carries, give no chance of save or recovery of that stroke.

Which isn't a solution, I know.

I tend to look at par a bit less precisely, with a lot more emphasis on "expected score" than "errorless play". I'll look at the most common score, and the median score, and the average (weighed in that order), to conclude what score I expect.

I'm not sure what to expect on that 20/20/20/20/20 hole, but the median and average are the same, and I can live with "too many" eagles. I'd wonder if it's a well-designed hole, though of course par has to be set on holes as they're found, well-designed or not.
 
Steve West said:
I'm thinking about a possible refinement to my formula for setting par by scores.

I'm satisfied that my current method will not set a par that is too low. (It sets par so that every throw has at least a 76.7% chance of leading to a par score.)

Now, I'm considering something to make sure it does not set par too high. Here is what's happening.

TDs and course designers are finding ways to get more scoring separation. This presents a challenge to any method for setting par. The more the scores are smeared out, the less obvious which score is the "expected" one.

For example, say the "expert" on the hole gets a scoring distribution of 20%x2, 20%x3, 20%x4,20%x5, 20%x6. Per my method, this would be par 4 because only 73.6% of throws contribute to a score of 3 or better.

73.6% = (20%+20%)^(1/3)

The average is also exactly 4. So far, so good.

Here's the problem. There shouldn't be that many eagles. To get an eagle, a player needs to make one throw that does the work of three throws. Or, make two throws that do the work of four throws.

As an example, a 1000-rated MPO player can get par with 427-foot drives, so an eagle that results from good drives would require one 1281-foot drive, or two 854-foot drives, or three 711-foot drives. Not impossible (especially for a player rated higher than the 1000-rated "expert") but it should not happen 20% of the time by players at exactly the skill level of an expert.

The holes where I'm seeing these spread-out distributions seem to be water carries. Maybe some artificial islands.

Making the water carry and gaining two throws on the other experts doesn't mean the players who cleared the water beat "errorless play" by two throws, it means that a lot of experts are making the two-throw error of throwing into the lake.

What I'm thinking is that there might be some cap on eagles. To me, 20% eagles is too many. In the 20/20/20/20/20 example, this rule would kick in and set par to 3. If 40% are getting 3 or better, and half of those players are getting 2, is anyone going to think that the scores of 4 do not include an error?

Thresholds for low percentages are tricky. Maybe it shouldn't be a flat percentage, but a count of the actual number of eagles. For example, I could see ignoring one eagle from the experts, even if there were only 5 experts.

Or maybe we could look for a way to identify the scores that resulted from two-throw errors and discount that effect somehow.

Your thoughts?
Click to expand...
If an "expert" is defined as a field of players within the same distance/skill range, and 20% are getting the lowest score in the distribution, it makes the case from my contention that a better way to set par would be "best reasonable score (BRS) + 1" for a distance/skill level where their BRS occurs at least say 5%(?) of the distribution on that hole. If 5% is too high for a reasonable eagle percentage, I'd be okay changing the proposed 5% threshold down to say 2% or 3%.

The unrecognized "flaw" (until recently) in setting par the way you've promoted incorporates higher scores in the distribution that include "errors" in the calculation. The proposed BRS+1 method works from the errorless play value (BRS), recognized by many as "scoring on a hole", with Par being BRS+1, not so much an error but just "not scoring" on the hole. Any scores thrown higher than par set via BRS+1 are a result of errors. Their distribution and percentages do not enter into the determination of par for that distance/skill level.
 
Cgkdisc said:
If an "expert" is defined as a field of players within the same distance/skill range, and 20% are getting the lowest score in the distribution, it makes the case from my contention that a better way to set par would be "best reasonable score (BRS) + 1" for a distance/skill level where their BRS occurs at least say 5%(?) of the distribution on that hole. If 5% is too high for a reasonable eagle percentage, I'd be okay changing the proposed 5% threshold down to say 2% or 3%.

The unrecognized "flaw" (until recently) in setting par the way you've promoted incorporates higher scores in the distribution that include "errors" in the calculation. The proposed BRS+1 method works from the errorless play value (BRS), recognized by many as "scoring on a hole", with Par being BRS+1, not so much an error but just "not scoring" on the hole. Any scores thrown higher than par set via BRS+1 are a result of errors. Their distribution and percentages do not enter into the determination of par for that distance/skill level.
Click to expand...
Par is not: Expected score with errorless play plus 1. Just read the definition.

I will give BRS+1 the credit it is due, though. It works fine in the narrow, groomed, confined, monotonous, homogonous spaces of ball golf. Where there are no poorly designed holes, virtually no trees, no OB in the fairway, and not as much difference in skills. Of the 918 ball golf holes used on tour, 917 would be assigned the same par using either BRS+1 or my method of setting par.

BRS+1 does not work as a method to apply to ALL disc golf holes. No one believes a 4 is the expected score when everyone gets a 3. Everyone knows that not all disc golf holes are designed in a way that allows a chance of gaining a throw on the competition (intentionally or by lack of designer skill). Especially when many divisions play courses that are not designed for their skill level.

However, there may be a place for BRS+1 as an additional constraint on par. Perhaps par should be set no higher than one more than the score that some target % of players get. (That % should vary by par to reflect the cumulative probability of making par-1 good throws in a row.)
 
DavidSauls said:
The difficulty of determining par by an errorless rate on each throw, is that all errors are not created equal.

Some errors give the thrower a reasonable chance at a save, with not just an average subsequent throw, but an above-average subsequent throw. Some give a slight chance of a save, with a great subsequent throw. Some, particularly water carries, give no chance of save or recovery of that stroke.
Click to expand...
This raised my curiosity about how often a throw actually affects the final score. It relates to the poll I can't get rid of up there. I ran the numbers against a whole lot of scoring distributions. I found that almost 80% of throws are of a quality that they would lead to the player getting the most common score. About 10% are good enough or bad enough to lead to the player getting a score one higher or one lower than the most common score. And only about 0.3% are so bad or good that they lead to a score which is two higher or lower than the most common.

Note this does not mean that all scoring distributions are 10/80/10. The effect is cumulative over several throws. For example, if the most common score was 4 the most typical distribution would be 01/20/50/20/06.
 
Imported from another thread:

Cgkdisc said:
"Your way is ineffective for designing holes in advance or correcting them when the data shows the design for scoring needs tweaking. Has nothing to do with our "official" par definition that we and all of the posters suffering through thousands of posts recognize doesn't always allow birdie scoring like ball golf. Every ball golf hole that meets their par definition is reasonably birdieable by players of the skill/distance level that hole was designed for. Our current disc golf par definition does not always allow that. Now, there's a better way being developed to design and make sure reasonable birdie scoring is possible by first designing for reasonable birdieability in your Par 3s, 4s and 5s. The parameters are not too different from existing DG par design parameters, just easier and likely more effective to apply in advance of scoring data."

Set aside talk about my method, that's not at issue. My method is not the definition of par and attacking it will not attack the definition of par.

The ball golf definition of par and the disc golf definition of par are the same. The score expected of an expert. Nothing in either definition prevents any kind of hole design.

The definition in both sports would label a hole a par 3 if everybody got a 3. Calling a 3 a birdie on that hole could never be the result of any sensible definition of par.

There are two reasons golf has almost no (but not zero) unbirdieable holes:

First, they just discard the holes that are unbirdieable and remake them so they are.​
​
Second, scores are much more tightly related to distance in ball golf. By excluding certain distances they can create a gap in scoring between par 3 and par 4.​

See this chart from http://www.stevewestdiscgolf.com/DoesReachPlusTwoWorkForDiscGolf.pdf
Unbirdieableability.png
The definition of par is not one of the reasons.

I support your new method of designing holes. You will run into the difficulty that scores in disc golf are so loosely tied to scores that merely setting limits on distance will not automatically avoid all unbirdieable holes. You will need to use additional parameters. Elevation and foliage certainly, but that won't be enough.

All I'm advocating for is that if it turns out to be impossible to create a foolproof method to avoid designing unbirdeable holes, you don't resort to the cheat code of always calling the lowest score plus one "par".

Think it through: If one-more-than-the-lowest-score was the definition of par, all the holes in the world would be "birdieable" no matter how poorly designed and no one would have incentive to design holes with your new method.

You WANT the definition of par to stay the same so you can test whether your design techniques are working or not, and to give designers incentive to use your techniques.
 
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