Ratings Guide
The below document is a © of the Professional Disc Golf Association
Read more about player ratings at PDGA.com
The PDGA Ratings Committee calculates player ratings from all PDGA Tour singles events where the TD has submitted timely, complete and verifiable information. Ratings are not calculated for doubles and team events, or for events where the TD is very late in reporting or submits incomplete information. It usually takes between one and three months after an event has occurred for the official calculation of player ratings to be completed. Your TD has the option to post results online at the PDGA website during or after a tournament where you will be able to see your unofficial ratings for rounds you played. In 2008, current PDGA members can expect to see their official player ratings updated and posted at www.pdga.com near February 1st (final ratings for previous year), late April, late June, early September and late November along with a handful of correction updates as needed.
All properly reported PDGA events for the past 12 months are included in a player’s ratings calculation. If you have less than 8 rounds of data, the program will go back as far as 24 months until it either finds 8 total rounds, or it will select all your rounds if less than 8. All members should receive a rating even if they only have one round of information in the database. Almost all of your rounds are counted, but those more than 2.5 standard deviations or more than 100 points below your average are dropped (about 1 in 50). Your most recent 25% (1/4) of your rounds will be double weighted in the calculation so your current performance is slightly more important. If you do not complete a round (indicated in event scores as DNF or 999), it is not included in your ratings round count.
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.
Should you have any questions regarding the player and course rating system, or your own player rating, please contact the PDGA Ratings Committee at ratings@pdga.com.
