OT - Ever seen the Playing Conditions Calculation used for handicaps?

[A.G._Crockett]

I just returned from a few days at Cabot Links and played in very strong winds for three days.  I entered my scores which, were well above my handicap (diffs of 9.6-18.4 for a 8.3 handicap) and there was no PCC applied on any of the days.  On some days it was at least a three club wind.  I guess Golf Canada didn't have enough scores entered to make an adjustment.


So thanks to the lack of PCC I look forward to my handicap going up a bit in the near future!

Wayne,


There can be a PCC adjustment with as few as 8 acceptable scores submitted on a given day on a given course.  So unless you were playing all three days on otherwise empty golf course, this is an example of what Erik referred to as the “conservative” nature of the PCC algorithm.


While the PCC is not simply about weather conditions, suppose, for instance, that Cabot Links is very windy most of the time, and that regulars there have indexes that reflect playing in those conditions. (I have no idea if either of these thing are true.) If the three days you played were at least somewhat typical, then scores would reflect that, and we wouldn’t expect to see a PCC adjustment.


On the other hand, if most of the golfers on a given day have indexes not derived from playing in extremely windy conditions, such as a tournament, then we’d expect to see many scores that were enough higher to kick in the PCC.


Whatever the case, if your index DOES go up, I hope you win money back home!

[Erik J. Barzeski]

There are many "bare bones" handicap calculators available for free on the internet.  Google it.  They don't have PCC but that's a very small point for somebody who wants a handicap to play friendlies with other like-minded players.

Yep. I don't think the inability to apply PCC is the "barrier" that Matt thinks it to be.

As I'm sure you know there has to be a minimum of 8 scores posted.  One score doesn't cut it.

I know, yeah.  I was being hyperbolic. Eight people averaging +1 over their "expected" scores will not result in a +1 PCC adjustment.

I don't know why you think the system is more "comfortable" with more data.

I put the word "comfortable" in quotes because it's not quite the right word but I thought people would understood what I was saying there. I guess I thought wrong. The algorithm not only accounts for the scores shot but the number and variety of players who shot them. If a +1 PCC is triggered by 60 people shooting some set of scores, ten people shooting those same types of scores will possibly/likely not trigger a PCC. Hence, the algorithm is more "comfortable" applying a PCC with more data, while still being "conservative."

I just returned from a few days at Cabot Links and played in very strong winds for three days.  I entered my scores which, were well above my handicap (diffs of 9.6-18.4 for a 8.3 handicap) and there was no PCC applied on any of the days.

Mostly curious: did you enter them the same day you played? The PCC is effectively applied at midnight, so only scores posted that day are considered by the algorithm. (You probably knew that, but others may not.) And posting more scores doesn't re-calculate the PCC.

[Carl Johnson]

I shows up in my handicap calculations in the USGA GHIN system.  I know I've had a number of +1's.  Not that I know which way that goes, or that I care.  I post and whatever happens happens.

[Erik J. Barzeski]

I shows up in my handicap calculations in the USGA GHIN system.  I know I've had a number of +1's.  Not that I know which way that goes, or that I care.  I post and whatever happens happens.

A +1 raises the course rating by one point (i.e. 68.3 becomes 69.3), thus reducing your differential by about a "stroke" as well.

[Matt Schoolfield]

Lock-in has a very negative connotation.  To me it's more about protecting their intellectual property.

I guess my question is protecting it from whom? The WHS is owned by the organizations with de facto monopolies in their respective countries, we're all members. It's also very odd to me considering game rules are not patentable or copyrightable. I seems entirely superfluous, especially since they control all the data behind the adjustments, which is why it seems like something an MBA came up with. The only reason why I see it as possibly making good sense is that in the last USGA financials that list GHIN revenues and expenses, the USGA lost a significant amount of money on the GHIN system (however GHIN revenues and expenses are no longer directly listed).

I think you misunderstand the PCC.  There is no PCC database.  Every day the GHIN system calculates a differential for every player who posted that day to update their handicap.  Peripherally it calculates the standard deviation of the difference between the posted score and the expected score for every player that posted and figures out if it needs to adjust those players' differentials because it was a much harder or easier day than expected. I suppose if you wanted to go crazy you could ask GHIN to send out a notice to all third party handicappers the PCC for every course so that the third party could incorporate it into their algorithm.  But, I can't see any reason why the USGA or any other association would want to do that.

I don't know how the data is stored, but I can't imagine they wouldn't store the PCC adjustments (even if the adjustment were a function and not just a number), especially for folks that forget to post day of (after they get a stern finger wagging). You could store the PCC adjustment directly with the player, but a dramatically more compact way to store the data would be an object with dates, courses, and their PCC adjustment. This gets into the weeds about database optimization, but I certainly hope they aren't attaching PCC adjustments to individual rounds in a database, without any way to double check whether an adjustment was made on a specific date. Assuming they do store this data, it would be fairly trivial and cost almost nothing to allow 3rd parties to query this database table, assuming reasonable behavior, and rate limiting.

The rest of the comments I can't really argue with. I fully agree it's not a big deal, and we just have a small difference of opinion.

[Bryan Izatt]

I just returned from a few days at Cabot Links and played in very strong winds for three days.  I entered my scores which, were well above my handicap (diffs of 9.6-18.4 for a 8.3 handicap) and there was no PCC applied on any of the days.  On some days it was at least a three club wind.  I guess Golf Canada didn't have enough scores entered to make an adjustment.


So thanks to the lack of PCC I look forward to my handicap going up a bit in the near future!

I looked at your scoring history on Golf Canada and none of the recent ones look like Cabot.  If you posted, I'm not sure where they went. You do have a PCC on the second most recent score of 85.  It doesn't tell me the date or the course, but you played the silver tees with a rating of 68.4 and slope of 123 and it was in September.


Your index is based on best 8 scores of last 20.  Your best 8 are mostly in the middle of your last 20 scores, so I wouldn't count on your index going up any time soon.  And the 9.6 differential at Cabot is pretty close to the top of your best 8 scores so won't hurt your index much.

[Bryan Izatt]

.....................

I don't know why you think the system is more "comfortable" with more data.

I put the word "comfortable" in quotes because it's not quite the right word but I thought people would understood what I was saying there. I guess I thought wrong. The algorithm not only accounts for the scores shot but the number and variety of players who shot them. If a +1 PCC is triggered by 60 people shooting some set of scores, ten people shooting those same types of scores will possibly/likely not trigger a PCC. Hence, the algorithm is more "comfortable" applying a PCC with more data, while still being "conservative."

Not to belabour the point, but, has the USGA shared their PCC algorithm with you? If not, then the above is your belief about how it works re the impact of the number of scores on whether the PCC is triggered.

The following is what Rule 5.6 says about calculating the PCC.  Not completely helpful but here it is.

The playing conditions calculation (PCC) will be an automatic calculation and can be summarized as follows:
1.  Calculate the expected score for each eligible player.

2.  Calculate the expected standard deviation of Score Differentials at the golf course incorporating all applicable Slope Ratings

3.  Establish how many players scored better or worse than expected on the day.

4.  The proportion of players submitting a score equal to, better than or worse than their expected scoring range determines whether a PCC adjustment is required.

5.  If an adjustment is required, determine how much harder or easier the golf course played that day.

6.  Based on these calculations, determine any final adjustment required for play on that day.

7.  PCC adjustment is applied as a whole number.

The premise is that it gets activated if there are 8 or more scores posted before midnight at a particular golf course.  My guess is that the system calculates the Standard Deviation of the expected scores of those 8 or more scores.  And, then they count the number of scores that are more than one SD greater than the expected average.  If the percentage of scores exceeding the average + one SD is more than 68% then the PCC is +1.  If 95% score more than the expected average + two SD then the PCC is +2.  If 99% of the scores are more than the average + three SD then the PCC is +3.  There is no mention of the number of scores factoring into the calculation other than the base requirement of 8.  I suppose the statistically minded around here might weigh in on whether the Standard Deviation of expected scores is somehow more reliable with 80 rather than 8 players keeping in mind that the counting of scores exceeding one, two or three SD's are the same 8 or 80 players who were used to calculate the expected Standard Deviation.


I really hope that the USGA has revealed the algorithm to you and you can definitively put this to rest. [/li][/list]

[Erik J. Barzeski]

it seems like something an MBA came up with
…
the USGA lost a significant amount of money on the GHIN system

Oh boy.

Not to belabour the point, but, has the USGA shared their PCC algorithm with you? If not, then the above is your belief about how it works re the impact of the number of scores on whether the PCC is triggered.

No, they haven't, and yes, the number of scores is a factor in the algorithm. Heck, it's a factor in a standard deviation calculation. Plus, I've been told this directly and have no reason to doubt the person who told me.

By not publishing the formula, or sharing it much, they're able to more easily change it should they need to, as well.

[Carl Johnson]

I shows up in my handicap calculations in the USGA GHIN system.  I know I've had a number of +1's.  Not that I know which way that goes, or that I care.  I post and whatever happens happens.

A +1 raises the course rating by one point (i.e. 68.3 becomes 69.3), thus reducing your differential by about a "stroke" as well.

Thanks.  As I recall these were bad weather days when the course was playing more difficult, so that makes sense.