I'm also curious as to how the rating system developed. I'd like to know the formulas involved too. Chuck, could you send me some info. on any details you might have.

From what I've gathered, WCP's were originally set for a few courses. Then players played these courses and established a player rating. At some point the system changed? and both SSA's and round ratings are now determined by the players� ratings and round scores only.

It's been hard for me to put this into words, but I'll try. It seems to me that the whole accuracy of the player rating system depends on the accuracy of the course ratings and player ratings when they were figured out originally, at the beginning, from scratch. What I mean is� player ratings come from round ratings, which come from player ratings, which come from round ratings, etc. WCP has nothing to do with it, only how well everyone did compared to existing ratings/ round scores at a particular tournament. It seems that any possible inaccuracies would be multiplied over time rather than cancel out. The hundreds of current players with ratings all came from the original few who developed their ratings from a few estimated WCP's. Do the numbers naturally stay accurate in a seemingly "closed" system? I can't help but notice how consistent and accurate the ratings seem to be. 1000 is a great par which pro's can measure themselves against. Is there anything that needs to be modified in the rating system to keep it accurately maintained over time?

I don't know too much about the history or the math involved with the rating system. I might be way off base here. I would like to find out more and know that I have it straight. :cool:

A few threads to look through.

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=62621&page=6&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63562&page=5&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63153&page=5&view=collapsed&sb=5&o=&fpart=1

The 1998 Pro Worlds in Cincy was the start of ratings. We used the average of the 100 best scores by 100 different players on each of the 4 courses to determine the SSA (was called WCP then). The assumption was that the average of 100 would yield the score of the 50th best player, and at the time, 50th place was close to the cash line in Open. We decided that would be called our scratch player with 1000 rating, someone who was near the last cash line in a major event. Players better than that would be our World Class players. Amazingly, 1000 rating has remained pretty close to what players need to shoot to cash at an A-tier or higher.

A few threads to look through.

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=62621&page=6&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63562&page=5&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63153&page=5&view=collapsed&sb=5&o=&fpart=1



Those threads have been gone for a while now. There are a ton of threads on the subject. Guess I have some reading to do...

Where are the mathematics broken down?

I just announced that we updated all of the documents in the ratings section of this site.

I just announced that we updated all of the documents in the ratings section of this site.

Your announcement got trumped by Chapman's announcement a couple hours later! :D Also, even though you put some updated document on the website, if you try to find the documents intuitively, like going to the player ratings page and clicking on the links, those links go to the old documents.

A few threads to look through.

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=62621&page=6&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63562&page=5&view=collapsed&sb=5&o=&fpart=1

http://www.pdga.com/msgboard/showflat.php?Cat=&Number=63153&page=5&view=collapsed&sb=5&o=&fpart=1



Those threads have been gone for a while now. There are a ton of threads on the subject. Guess I have some reading to do...

Where are the mathematics broken down?



Kinda interesting.

Does anyone know if they do ratings on a nine hole round. I sucked at Z Boaz my last nine and I hope that does not affect my rating.

Only rounds with more than 12 holes are rated.

There goes my 1089 round. :DFro now on I vote for final 12's instead of nines so we can at least get a rating. :D

More than 12...

Final 12.1 :D

.

Why can't all rounds, regardless of # of holes be rated?

Given the set number of propegators play the same configuration.

I think, that if you play it, then it gets rated. There are plenty of holes and partial rounds I wish were not on my rating. But that is why you play more consistent and lower that SD.

Is that so wrong?

It's like comparing halftime stats to full game stats. Someone who shoots 68% in the first half can't be compared to someone who shoots 55% for the game. In fact, a case could be made that ratings should only be done on 18-hole rounds or maybe 15-21 holes only.

well I think that ratings should be used on any format from 12-27 holes although I think the 27 hole rounds should be weighted 1.5 times, 24 hole rounds be rated 1.3 times and 12 hole rounds rated at .67 times a normal 18 hole round. This way the ratings wouldn't skewed from different amounts of holes being played. 2 rounds of 27 holes rated at 1000 should be weighted the same as 3 rounds of 18 holes, should it not???

is the ultimate goal to have all courses ranked, if so then individual holes would be assigned a ranking and in that case as long as the layout was indicated you could establish player ratings even on a three hole playoff...

Just like in ball golf I would love to see a scorecard with hole handicaps or ratings on it.

One point in favor of not counting final nines is that strategic play may be involved more than in regular rounds. A player with a multiple stroke lead may be playing very safe golf while a player that is multiple strokes behind may be playing very dangerous routes (that they would not normally play) trying to gain strokes on the leader.

Ratings for these rounds could be very misleading.

One point in favor of not counting final nines is that strategic play may be involved more than in regular rounds. A player with a multiple stroke lead may be playing very safe golf while a player that is multiple strokes behind may be playing very dangerous routes (that they would not normally play) trying to gain strokes on the leader.

Ratings for these rounds could be very misleading.


I agree with this. I think ratings should only be assessed for 18+ hole rounds. And definitely not for playoffs.

Just like in ball golf I would love to see a scorecard with hole handicaps or ratings on it.



We had Gold scoring averages from our test events on the PW2001 scorecards along with lengths in feet and meters for our international players.

One point in favor of not counting final nines is that strategic play may be involved more than in regular rounds. A player with a multiple stroke lead may be playing very safe golf while a player that is multiple strokes behind may be playing very dangerous routes (that they would not normally play) trying to gain strokes on the leader.

Ratings for these rounds could be very misleading.



I can agree with this reasoning. Heck, even going into the last hole of a regular 4th round you have different strategies depending on your lead. It is not the same golf, so I would only imagine that mentaility for a final nine.

If a 1000 rated player shoots a 4 playing one hole, it would be rated 1000. A non-propagator who shoots a 3 gets about a 1125 rating and a non-propagator shooting a 2 gets around 1250. As more holes are completed, the range of top and bottom ratings among the pool of players keeps narrowing. A player who wants to boost their rating would seek events where 15-hole courses are used and throw terrible in the last half of the round so it gets dropped if the first half isn't really hot.

Obviously, we don't want that happening but it's getting uncommon to see courses with 14-17 holes on PDGA reports anyway. Some TDs know to report 12-hole rounds as 24-hole rounds by combining them so players get ratings. That doesn't hurt anything because the range of ratings keeps narrowing the more holes in a round. It wouldn't help to more heavily weight rounds with more than 18 holes because there's a good chance they won't be your best rated rounds.

It wouldn't help to more heavily weight rounds with more than 18 holes because there's a good chance they won't be your best rated rounds.



by that same logic, wouldn't one's rounds on courses with higher SSA's have a good chance of not being one's best rated rounds? :confused:

Yes, that's been well discussed. It also will likely not produce your worst rated rounds either.

serious question: why do we need individual holes rated?

Maybe this is coming from ignorance and a lack of play on multiple ball golf courses. I think I may have only played on 15 different golf courses in my life.

But it seems there is a lack of differentation between ball golf holes. At least in context to how disc golf holes are designed.

What I am saying, is that there are more obstacles in disc golf then ball golf as a percentage of fairway space. This is purely a matter of the overall size difference.

But from what I have observed is that the only way to really make a ball golf hole tougher is to make a tougher green. We in disc golf seem to have a lot more options to increasing the difficulty of the hole, besides mandos and yellow ropes (Dave Mc.).

So it seems that it would be much more difficult to rate individual holes instead of doing a subjective analysis of the players performance that day in comparison to other players, weighted on their past performances (ie player ratings).

Unless the PDGA is going to pay Chuck 6 figures to sit down and rate individual holes, then I personally feel this would be a waste of resources when those could be applied to perfecting the ratings equation.

Just my opinion. And maybe someone who knows more about ball golf course design can chime in on differentation of holes in that sport.

Depends on what you mean by "rating" the holes? We're attempting to do quality ratings of holes in the PDGA Course Eval process. Getting scoring averages per hole is regularly done in ball golf to determine handicap rankings. I see more designers and course pros starting to track scoring averages and distributions on their holes but there's not an organized place to publish the results. More education in this area will be needed because adjusting the numbers to specific skill levels is a bit more complicated process. We haven't seemed to have as much interest in handicap play among PDGA members as the broader base of recreational USGA members in ball golf, so there hasn't been as strong of a need for individual hole stats for scorecards yet. However, now that we have ratings and better identified skill levels, demand will likely increase for this information.

But from what I have observed is that the only way to really make a ball golf hole tougher is to make a tougher green. We in disc golf seem to have a lot more options to increasing the difficulty of the hole, besides mandos and yellow ropes (Dave Mc.).



Ball golf has a load of variables that affect play. Fairway width and length, hazards like water or bunkers can be either near the green or on the fairways, OB, trees, elevation, height and thickness of rough, etc. Stick golf requires strategic and tactical execution, too.


Unless the PDGA is going to pay Chuck 6 figures to sit down and rate individual holes, then I personally feel this would be a waste of resources when those could be applied to perfecting the ratings equation.



Couldn't the data from tournament scorecards be used to generate hole ratings? Or is hole rating a matter of individuals making decisions as to difficulty of play ?

Scores from scorecards work fine to determine hole scoring averages if people are willing to do the work. The tricky part is adjusting the averages to a specific rating.

Despite all of those elements on ball golf courses, adjusted length is overwhelmingly the primary indicator of scoring average. Vertical fairway elements in disc golf play a much bigger role impacting scores but length is still the primary element to predict scoring average.

"Happy Birthday Chuck" !!!!! Nice call on this .................Vertical fairway elements in disc golf play a much bigger role impacting scores but length is still the primary element to predict scoring average.

Does this also help course ratings ?

Does this also help course ratings ?



Trees certainly add to the potential quality rating of a course. Hills, trees and water mixed in the right amounts would be my formula to potentially build a great course.

I didn't know this thread was still going.


I support tee signs that would state the hole's difficulty factor. This would be the scratch (1000 rated) hole scoring average. Rounded into tenths, the number would read like.."2.8". Players could compare their own rating to this and know what par would be specific to them.


On a different note, I have another question. I've been asking about how the ratings work for a long time. Mathematical description is what I'm looking for.

Anyways, I recently played a C tier at Wyandotte County park in KC and I noticed the the "pre" ratings show that almost every player shot better round ratings than their player ratings.

I thought these two (round ratings and player ratings) were supposed to balance out. I thought SSA had nothing to do with round ratings, as well as conditions such as weather and wind... because everyone had to deal with the same.

Struggling with the basic concept here. If I am, I know almost everyone is.

The average of the propagator ratings is about equal to the average of the round ratings of the propagators. Let's say you have an event where there are 40 players but only 5 are propagators (unlikely but for this example). If the average rating of the 5 props is 900, the average of their round ratings will be around 900 no matter how well they shoot. If these five played relatively poorly compared to the rest of the players who have ratings (but not enough rounds to be props yet) the round ratings of the non-props may all be higher on average than their current ratings.

Thanks Chuck,

You seemed to have noticed that I forgot that not all the players are considered propagators.

I didn't know this thread was still going.

This thread never ends. It is constantly being reborn under different names. It is making me completely rethink my conversion from Hinduism to Christianity! :D

Chuck, here's something that makes no sense to me:

If a new member has exactly two rated rounds in his database, a 939 round and a 1006 rated round, shouldn't his rating be the average of the two? I was looking at some player stats for players I don't know coming to my tournament, and that player's rating was 984. Check it out. (http://www.pdga.com/tournament/player_ratings_detail.php?PDGANum=29274&year=2006)

That 1006 round got double weighted giving the 984.

Something being discussed is modifying the policy for those whose rating is based on less than the propagator level of 8 rounds. Should we flag the ratings of props versus non-props? Should we allow players more flexibilty to enter divisions lower than their rating if it's based on say less than 4 rounds? Should we not even display a player's rating until it's based on at least maybe 4 rounds? We think something needs to be done in this area and are looking at the alternatives plus the programming resources necessary to do whatever might be decided.

If non-propagators' ratings appeared in red italicized font everywhere their rating is shown, that would be cool. It would be useful for a lot of things. I played in a tournament not so long ago where there were 15 or 20 rated players in rec and the TD assumed they had enough propagators that he could give them short tees. They didn't. If those players all had red ratings, the TD might have known just from having uploaded his pre-reg and from having looked at it from the Tour page to make sure it uploaded ok.

On the other thing, I'd rather see those players get a trophy-only option than get a free pass to whatever division they want to play. Once you take the mandatory ante out of the equation, there's no unfairness in just playing where your rating puts you.

I've wanted the propagator ID for a while for the very reason you mentioned so that TDs know whether enough props will be playing if they use different course layouts for some divisions.

Chuck,

forgive me for my ignorance on the subject. I really don't have any plans on playing of playing anymore events until the next ratings come out. Would my rating go very far with only my 3 rated rounds from this weekend?

I'm 1016
played 1055, 1010, 1045

so do I get to claim those 3 rounds and then average them with my current rating?

The reason I ask is I'm hoping to squeez in the ACE Skins at MSDGC

Chuck,

I do believe that a player should have at least 8 rounds before a rating is issued. There are several reasons, but a single set of four rounds generally will tell you how well someone throws on one course. A lot of times that course is their home course. Players should play better on their home course giving them an artificially high rating. Another reason is that TD's still make mistakes on their reports. A failure to report that the Intermediate and Rec divsions played on shorter tees than the Open divsion will cause invalid ratings. By having at least 8 rounds that should average out a bit. If you look at the current top rated am players, two of three of them have only three rounds or less for their rating and they are both rated very high. Now maybe they are that good, but with only three rounds to show, it is hard to say.


That 1006 round got double weighted giving the 984.

Something being discussed is modifying the policy for those whose rating is based on less than the propagator level of 8 rounds. Should we flag the ratings of props versus non-props? Should we allow players more flexibilty to enter divisions lower than their rating if it's based on say less than 4 rounds? Should we not even display a player's rating until it's based on at least maybe 4 rounds? We think something needs to be done in this area and are looking at the alternatives plus the programming resources necessary to do whatever might be decided.

Chuck,

Can you tell me why there isn't any ratings for the Texas Womens Championships for the Finals?

Is it just a glitch with the program?

Kevin,

Probably because it's listed as a finals round. I believe the system won't rate finals, because they're normally only 9 holes. Chuck and his crew normally rate those 18 hole finals later. We could relist the finals round as a regular round so you could see the temporary rating online now, or you could wait until the next ratings update in June, and the rating should show up then as a final rating.

Chuck may have a better answer.

Chap

Rounds must have at least 13 holes to be rated.

Yeah and they were 18. :D

I didn't write the software for online but I'm guessing that rounds listed as Final don't get rated. If the info was entered as Round 4 then the calcs would have been done.

thanks for the info

Kevin,

I re-uploaded the scores as a 4-round event, so the temp rating for round 4 is now available online.

Chap

Kevin,

I re-uploaded the scores as a 4-round event, so the temp rating for round 4 is now available online.

Chap



Is the 3rd round for FW3 set as a different layout? They played shorter tees.

THANKS!


C Peavy will be glad to see that 972 ;)

Is the 3rd round for FW3 set as a different layout? They played shorter tees.



It is now. Thanks for the heads up.

Chap

John or Chuck.

Could you guys check the ratings for Paul Giles Memorial, April 30-May 1. It appears to me that the wrong format has been entered. It should be three 24 hole rounds and I believe it is online as three 18 hole rounds.

Also, why should it matter how many holes were played? Shouldn't the rating calculate out the same? What the current calcs suggest is that if you play a more difficult course (higher average scores) you will be rated lower. Shouldn't the average be the same as long as you have a sufficeint number of propagators???? I understand how the equation works, it is the common sense part that I am asking about.

Since I have started, why is it that if you have X number of 800 rated players all shooting the same score they end up with a higher rating? Once again I know how the equations work, it is just common sense. If twenty 800 rated players all shoot 54 then they should all have shot an 800 rated round, but that is not how it calculates out.

Is there any chance that a rule will be introduced that will make people play pro if there rating reaches a certian number? That way we can get these 970 rated advanced players to move up.

Click...click...back....back....

No.

By definition, making the decision to turn professional is a choice, as is also remaining as an amateur.

You cannot force someone to play a sport professionally. The best thing you can do is encourage their improvement and get them to make the decision to move up.

We already have blurred definitions of amateur and professional divisions in this sport, forcing people to turn professional by an arbitary number is not the solution.

Is there any chance that a rule will be introduced that will make people play pro if there rating reaches a certian number? That way we can get these 970 rated advanced players to move up.



Another OKIE tired of SANDBAGGERS!!!! I hear ya brutha

Ask the TD to check the format for online posting if you have a question.

Twenty four holes is the same as 1.33 rounds and calculates like a higher SSA 18-hole course. It's the same reason that certain stats like shooting percentages for many sports are kept for whole games rather than just for a half. The longer the playing time, the narrower the distribution of performance.

The ratings function is a quadratic with a shallow curve that we force to a linear calculation. The adjustment is there to flatten that curve and make sure the numbers are fair for both 800 and 1000 rated players.

Paul Giles is currently entered as a single 24 hole layout for each round.

I played with a guy at Tarheel last weekend who was competing in his first PDGA event. His round ratings were 887 - 961 - 945 - 800(#3 meltdown). I tried to explain to him the SD formula but I didn't know about minimum number of rounds. How many rounds does he need to have before he may see some rounds excluded?

There is no minimum. Rounds get excluded if they are outside the 2.5 SD limit or more than 100 points, whichever is lower, for whatever number of rounds a player has.

Is there any chance that a rule will be introduced that will make people play pro if there rating reaches a certian number? That way we can get these 970 rated advanced players to move up.



Not if I have anything to say about it. Players should WANT to move up. If we remove some of the incentive to stay an amateur (hence by doing more player packs, and fewer prizes on the back end), many more will move up and test the waters.

Turning professional is a choice. You should not FORCE someone to be a pro.

Chap

Turning professional is a choice. You should not FORCE someone to be a pro.

Chap



We force people to move up to Intermediate when their rating is 875, and to Advanced when they hit 915. I see no reason why there shouldn't be a similar line for Pro. With our current tournament system structure and the financial state of the sport of disc golf, there is no difference between Amatuer and Pro except for ability and I'll neverstand why people keep insisting otherwise. When we're all playing for peanuts and each other's entry fees, and virutally no one makes a living from disc golf, I'll never agree that there is any distinction between amateur and pro other than ability. That there are a dozen "amateurs" with player ratings higher than 980 (http://www.pdga.com/player_ratings.php?offset=0&division=M1O&order=rating) (and the top disc golfers in the world are only slightly higher) is evidence of how silly and arbitrary this difference / designation is.

never mind

Turning professional is a choice. You should not FORCE someone to be a pro.

Chap




We force people to move up to Intermediate when their rating is 875, and to Advanced when they hit 915. I see no reason why there shouldn't be a similar line for Pro. With our current tournament system structure and the financial state of the sport of disc golf, there is no difference between Amatuer and Pro except for ability and I'll neverstand why people keep insisting otherwise. When we're all playing for peanuts and each other's entry fees, and virutally no one makes a living from disc golf, I'll never agree that there is any distinction between amateur and pro other than ability. That there are a dozen "amateurs" with player ratings higher than 980 (http://www.pdga.com/player_ratings.php?offset=0&division=M1O&order=rating) (and the top disc golfers in the world are only slightly higher) is evidence of how silly and arbitrary this difference / designation is.



If you look at the stats of everyone on that list, many of them have recently taken the next step and have started playing pro, some have not played enough tournaments to really have a proven record, and a couple are...well...baggers.

If you are 980+ and still playing AM, your only hurting yourself!

Do yourself and the rest of the PDGA a favor and MOVE UP!

I joined the pdga after playing DG for 2 years as a Open player. Never played a tournament other than Open.
Now a few seasons in, I'm glad I did what I did.

Do yourself a favor, MOVE UP!

Can anyone tell me why the Novice and Intermediate divisions did not get ratings at the Northshore Invitational in Fayetteville Arkansas on April 1st of this year?
I am not familiar with the system but there were many rated players at the tourney but noone in Novice or Intermediate got round ratings. Was this not a rateable category or was it not turned in for us or what?

Just curious DG'er who wants his rating to go up. /msgboard/images/graemlins/smirk.gif

Whenever you don't see ratings for some divisions, the primary reason is that there weren't enough players (5) with established ratings (based on at least 8 rounds) to calculate the ratings for that round. Just because you see a player with a rating, doesn't mean they are a propagator with a rating based on 8 rounds or more. We hope to come up with a way to identify those who are propagators online so that players and TDs can see whether there are at least 5 playing a particular course layout to know whether ratings will be calculated.

Chuck,

Just a suggestion, but if you include a column in the regional report showing that a player is a propagator, or qualifies as a propagator, that would be very helpful.


Whenever you don't see ratings for some divisions, the primary reason is that there weren't enough players (5) with established ratings (based on at least 8 rounds) to calculate the ratings for that round. Just because you see a player with a rating, doesn't mean they are a propagator with a rating based on 8 rounds or more. We hope to come up with a way to identify those who are propagators online so that players and TDs can see whether there are at least 5 playing a particular course layout to know whether ratings will be calculated.

We're reviewing the options and hope to provide propagator indications in more than one place.