# Your PDGA rating

#### Noill

##### * Ace Member *
I'm trying to figure out how the PDGA gets a players score. So I found this on the PDGA site:

How are ratings for an event calculated?
The scores thrown by propagators each round are used to calculate the SSA rating for a specific course layout. A propagator is a current member whose rating is over 799 and is based on at least 8 rounds. As long as there are 5 propagators playing a course layout, ratings can be calculated. The average rating of all propagators will equal the average rating they get for the round – always. If the same course layout is used more than one round, the scores from multiple rounds will be used to determine an overall SSA, as long as the individual round SSAs come out close to each other, so everyone gets the same rating for the same score on the same course. If the SSAs are significantly different, likely due to varying wind conditions, the round ratings will be calculated separately. If a propagator shoots more than 60 points below their rating, their score will not be used in the SSA calculations.

This seems a little odd to me at first glance. Does anyone have a better way of explaining it?

TIA

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All i know is shooting good= a good round rating.

Im sure cgkdisc knows a lot more and can help explain. Maybe pm him or wait for him to post here.

Which part are you confused about? The basic idea is that players who have enough rated rounds have their scores used to generate an SSA. The SSA is just a course rating for that round that's an approximation of what a 1000 rated player would throw. Based on that you get a round rating, usually it's about 10 points difference per stroke.

woops I copied the wrong one...

This is what I wanted some clarity on:

How is your rating calculated?
All rated rounds you have played and have been reported to the PDGA within 12 months of your most recently rated round will be included in the calculation. However, if any one of those ratings is either more than 100 points below your average rating or more than 2.5 standard deviations below your rating – whichever number is smaller – that round will not be included. That works out to about 1 in 50 rounds getting dropped. Rounds where you DNF (Do Not Finish) are never counted in your rating. The most recent 25% of your rounds get double weighted which slightly boosts your rating if you have been steadily improving. If a player has fewer than 8 rounds in the past 12 months, since their most recent round, then we'll go back up to another 12 months until we find up to 8 rounds but never go back any farther than a total of 24 months.

Seems like there is a lot of art to this science...

seems like you get 8 rounds counted in your score (averaged) if you've played 8 in the past 24 months. If you've been getting better then they double up your score of the most recent 25% to help you get a better rating? (how do we know if they've done that? if you are getting very similar scores then they don't do that I guess?)

so they take up to 8 rounds and average that and this is your rating... I think that's it basically...

I was just hoping someone could just say "hey dumba\$\$, it's like this....(insert brilliant explanation here)"... and feel free to drop the "hey dumba\$\$" part

There's nothing fancy in that. They take your rounds from the 12 months since your last rated round, then average them out. The most recent 25% of the rounds get double-weighted meaning they basically count each one once.

Let's pretend you only threw 8 rated rounds in the 12 months since your last rated round. It would look something like this (in order from most recent to oldest): 932, 975, 926, 889, 941, 915, 926, 913.

They would take the most recent 25% (the 932 and 975 rated rounds) and double them up, so the rounds they will count toward your rating will look like: 932, 932, 975, 975, 926, 889, 941, 915, 926, 913. Add them all up, divide by number of rounds (10 in this case), and you get your rating of 932.4 which I guess would be then rounded to 932.

If you shoot any rounds that are more than 100 points below your rating or more than 2.5 standard deviations below your rating, they will not get counted in the rating estimate. 100 points is pretty straight forward, finding standard deviation is a little more complex but you can use the calculator here: http://www.easycalculation.com/statistics/standard-deviation.php - in this case your standard deviation of the original 8 rounds is roughly 24.8 points so any rounds more than 62 points (24.8*2.5) below your rating will not be counted. If your rating is 927 currently and you shot an 857 rated round (70 points below your rating) it will not be counted.

Hope that clears things up for you.

That does... thanks notroman

it wasn't too difficult but I wanted to be sure I understood it properly

Simplified?

Most people who play tournaments, have played at least 12 rounds in the past year. That's 3 4-round events. So for the most part:

It's an average of all your round ratings for the past year, with the most recent ones (25%) given extra weight.

The rest is stipulations for people who've played less than 12 rounds in the past year. Or clarification that rounds you don't finish, don't count. Or the stipulation that a really bad round doesn't count (I guess to keep someone from really tanking a round to deliberately lower his rating).

Your seat's IQ, I'll let you figure out.

Close, but not quite. Every round you've played within the last year will be factored into your scoring with the most recent 25% being double-weighted. If in the last 12 months, you've had less than eight rounds, they'll go back to no more than 24 months ago and count the most recent eight rounds.

*edit - Beat to it*

Close, but not quite. Every round you've played within the last year will be factored into your scoring with the most recent 25% being double-weighted. If in the last 12 months, you've had less than eight rounds, they'll go back to no more than 24 months ago and count the most recent eight rounds.

*edit - Beat to it*

It's not the past year, but the year since your most recent rated round. If you haven't played a tournament since November 14th of last year, your ratings update this May 17th would include all rounds since November 14th of '09 (and your rating will not change).

There's nothing fancy in that. They take your rounds from the 12 months since your last rated round, then average them out. The most recent 25% of the rounds get double-weighted meaning they basically count each one once.

Let's pretend you only threw 8 rated rounds in the 12 months since your last rated round. It would look something like this (in order from most recent to oldest): 932, 975, 926, 889, 941, 915, 926, 913.

They would take the most recent 25% (the 932 and 975 rated rounds) and double them up, so the rounds they will count toward your rating will look like: 932, 932, 975, 975, 926, 889, 941, 915, 926, 913. Add them all up, divide by number of rounds (10 in this case), and you get your rating of 932.4 which I guess would be then rounded to 932.

If you shoot any rounds that are more than 100 points below your rating or more than 2.5 standard deviations below your rating, they will not get counted in the rating estimate. 100 points is pretty straight forward, finding standard deviation is a little more complex but you can use the calculator here: http://www.easycalculation.com/statistics/standard-deviation.php - in this case your standard deviation of the original 8 rounds is roughly 24.8 points so any rounds more than 62 points (24.8*2.5) below your rating will not be counted. If your rating is 927 currently and you shot an 857 rated round (70 points below your rating) it will not be counted.

Hope that clears things up for you.

Slight ammendment too... if you are trying to calculate your own. When you take the top 25% and that # of rounds takes only a few rounds from a multiple round event ... You would take the highest rounds from that event to satisfy the percentage...Very simple example. If you had 4 rounds... 930 940 950 960 you would take all those and then the 960 as the 25% that is doubled.

Which part are you confused about? The basic idea is that players who have enough rated rounds have their scores used to generate an SSA. The SSA is just a course rating for that round that's an approximation of what a 1000 rated player would throw. Based on that you get a round rating, usually it's about 10 points difference per stroke.

So based on the first question (that I accidentally posted) they take all propagators (those who have a rating above 799 and have 8 rated rounds) and average there scored to come up with the 1000 rated round for that event?

Would that be everyone playing on the field throughout the divisions?
For us to calculate it out, we'd have to identify all of the propagators and discriminate them from players with either below 799 and / or have less than 8 rated rounds... then average their scores to get the 1000 rated round?
If we do that, how do we get the point spread, i.e., how do we know if it is 10 points per stroke or 9.88 or 12.67?

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well, in the middle of writing this I checked and found my answers and WTH I'll post it just in case someone is interested...

Your rating for each round is based on how well you shoot relative to a scratch player who is defined as someone with a rating of 1000. The Ratings Committee can calculate your rating even if there are no 1000-rated players playing that round. In fact all that is needed are 5 players with ratings over 799 playing the same course whose rating is based on at least 8 rounds of information. These players are called "propagators."
The first calculation is to determine the Scratch Scoring Average (SSA) for each round. That score is what a scratch world class player with a rating of 1000 would be expected to average on that course. For example, let us say that SSA is calculated to be exactly 50 for an 18-hole course. Any player who shot a 50 that round would receive a rating of 1000 for that round. Each throw is worth about 10 rating points for courses with this level of difficulty. So, if you shot a 60, your rating for that round would be 900 because you were 10 throws worse than scratch times 10 points per throw. If you shot really well and scored 48, your rating would be 1020 for that round which is 2 throws or 20 ratings points better than SSA. All scores thrown on the same course layout in multiple rounds will be used to determine the SSA and ratings for that layout except when wind is significantly different.
The 10 ratings points per throw holds up well on 18-hole courses with SSA values within several throws either
side of 50. However, as a course gets much easier or much more difficult, the number of rating points per throw changes. In the case of a real easy course with an SSA around 44, every throw works out to about 13 rating
points. On really tough courses like Winthrop Gold at the USDGC with a SSA about 68, every throw works out to be about 6 rating points.
The reason that the ratings points per throw change over the range of course difficulties is an effect called "compression." Consider a real easy course. The top players can only shoot so well on this course, given they are limited to scoring no better than a 2 on virtually every hole. However on these courses, where the average hole is likely to be wide open and less than 250 feet, even lower rated players can shoot lots of 2s. This "compresses" or narrows the range of scores for players of widely varying skills in that round. On the other hand, a really tough course will spread the scores farther apart in each round when compared to a course with a scoring average of around 50 for scratch players.

*from http://www.pdga.com/files/documents/PDGARatingsGuide.pdf

i have a question here

if you shoot 60 points below your rating then it doesnt count towards your rating, i understand that but im wondering if bad rounds are dropped as your rating goes up over the 60 point threshold

for example your are rated 850 and have a two previous rounds at 795 that are part of that calculation. new ratings are calculated and your new rating is 865, are those bad rounds dropped or not until the one year mark?

I think that they would still count (your previous ratings) if you are at 865 and shoot a 765 then that wouldn't count

I think that they would still count (your previous ratings) if you are at 865 and shoot a 765 then that wouldn't count

^^Not necessarily true. In the explanation it is 100 points or 2.5 standard deviations (or something like that). So in my case I have had rounds that are around 60 points less than my rating get dropped.

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