Course Round Rating

[keith]

After enjoying the tread RD started about player ratings, I thought of another DG "Ratings" topic that has always baffled me; this is the topic of Course Round Ratings.

So in the Music City Open, the PRO players played rounds 1 and 2 at 7 Oaks. In round 1, a par score of "54" was given a round rating of 965. In round 2, a par score of "54" was given a round rating of 969. This was strange to me because the best score in round 2 was actually lower than in round 1. And by the way, the course was in the same condition (baskets were not moved) for both rounds.

Now to be really confusing, on Sunday, the AM players were playing at 7 oaks. In round 3, a par score of "54" was given a round rating of 956. Which by the way, was 9 points lower than the PRO players first round. In round 4, par "54" was given a 961. In this situation, the best score for that round dropped from round 3. By the way, the AM players were playing the course in the same condition as the PRO players. Baskets were all in the same position.

So.. what gives here. Why do these round ratings vary so much considering the fact that the course is in the same condition? And... why did the PRO rounds consider a par of "54" a higher rating than the AM rounds? After a PRO player shoots an amazing "43" in round 1, you would think a par "54" would be given a lower round rating than what was given to the AM players when there was no one even close to a "43".

Now this leaves me in such a quandary. So... maybe you more experienced tourney players can shed some light on this topic. At least to me, a course (as long as the baskets are in the same position and the trees have not moved) should have a static rating. But... that's just me. So enlighten me my DG friends.

Blessings,

Keith

[RD]

Ron will have a better answer, but I do know the factors that come into play besides pin placement are weather conditions

Wind and rain for example play a huge role. the weather wasn't that much different thus the ratings were off just a little.

but a two day that has sun on one day and rain on the next will drastically change it.

Its the short answer, Ron being a TD who has imputed the course conditions will have a better answer

[RD]

this may help too.

www.pdga.com/ratings

[Ron Pittman]

It's just math.

For example if you had 80 players rated 1000, and they shot all shot a 48 --- it would be easy to follow the math. A "48" is rated 1000.

So, in any given rated tournament round all existing player ratings are thrown into the mathematical pile with their actual raw score. Out the other end comes a rating -- for everybody with a ratings history --- for that actual round. Not as easy to follow as the first example, but exactly the same number crunching.

That is why any given pool of players can end up with a different number for each round. The raw data from each round is different -- so why wouldn't the result be different?

And RD is right; any number of variables exist that would generate a different rating to the same raw score --- from 2 different rounds. Any condition change from wind, mud, rain, dew, humidity, dryness of ground, etc. would be seen as a variable.

Even if one or two players shoot real hot or real cold --- that doesn't have the power mathematically to alter the result by more than a tenth or 2. Yes, The ratings do have a greater opportunity to be skewed in the case of a very small number of propagators, or if the propagators have a very short ratings history. (Sometimes the case if only an division or 2 play from different tees than everyone else. ) But, that is not the case in the MCO. Big field, plenty of data.

So, the question isn't "why are they different for different rounds", the real question is, "how could they possibly be the same?.

Ron