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  1. #1

    Default DSR formulas from GA

    Hey everyone,

    I've just been doing a bit of googling around trying to find out how GA calculate whether a DSR other than 0 is warranted at the conclusion of a competition round.

    Despite considering myself a decent Googler I have come up empty handed.

    While the DSR is referenced many times in many places in comms from GA, the actual formulas are not. It is also referenced in rules interpretations from the R&A and USGA and all seem to give a high level overview along the lines of "statistical formulas comparing how each player in the field scored compared to what they were statistically expected to score. If a sufficiently large number of players have shot outside that range then a DSR is in order". Those are my words by the way, not quoting any of those specific bodies.

    Anyway, does anyone have any insights into what those statistical formulas are?

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    Last edited by Maxbxl; 26th February 2022 at 07:43 PM.

  2. #2
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    I have seen how they calculate it somewhere, there is a handicapping manual, however its so complex its beyond human understanding, you dont have a hope in hell of checking or predicting.

    BTW its not GA's method its a world wide standard, so no reason for GA to publish it
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    Think it was listed in the explanation notes when we swapped to the new hcp system and haven’t seen it since
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  4. #4

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    Quote Originally Posted by markTHEblake View Post
    I have seen how they calculate it somewhere, there is a handicapping manual, however its so complex its beyond human understanding, you dont have a hope in hell of checking or predicting.

    BTW its not GA's method its a world wide standard, so no reason for GA to publish it
    Hey Mark thanks for the post. I agree that by all accounts it is fairly complex and would frighten most people (complex mathematical formulas usually do). I have concluded that that is the primary reason why they're not readily available.

    Also agree with you regarding GA not being the custodian of this calculation. I'd imagine (hope) that all organisations using the WHS would be using the same calculation for the DSR.

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  5. #5

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    Quote Originally Posted by Steve View Post
    Think it was listed in the explanation notes when we swapped to the new hcp system and haven’t seen it since
    Maybe when we moved from CCR to DSR? I wouldn't know. I still haven't found anything even growing through a bunch or older archived comms.

    The closest I've come so far is an old Reddit thread linking to the statistical formulas used by a non WHS handicapping organisation in the US. Granted they were fairly complex!

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  6. #6

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    I don't even think there is a DSR anymore.

    It's ACR and then PCC decides the daily factor


  7. #7
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    Don’t worry about formula, just relax and play golf.

    Whatever shots GA give you is a blessing. The more the merrier


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  8. #8

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    Quote Originally Posted by thecollective View Post
    Don’t worry about formula, just relax and play golf.

    Whatever shots GA give you is a blessing. The more the merrier


    Sent from my iPhone using Tapatalk Pro
    The search stemmed from a question from a mate asking why no DSR was applied today on a particularly horrendous day (anyone in Sydney would probably ask we'd bother playing at all tbh).

    I thought I'd look into it and it's now quite simply become my white whale! I feel the WHS formulas are pretty well understood and described in general including some less common ones like impacts of exceptional scores, but this DSR one remains mysteriously hard to find. And now I'm curious!

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    Last edited by Maxbxl; 26th February 2022 at 08:14 PM.

  9. #9

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    Quote Originally Posted by backintheswing View Post
    I don't even think there is a DSR anymore.

    It's ACR and then PCC decides the daily factor
    I'm pretty sure you are correct about the above and I've seen PCC and DSR used slightly interchangeably. But again as above the formulas for calculating the PCC are not easily available.

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    Quote Originally Posted by Maxbxl View Post
    I'd imagine (hope) that all organisations using the WHS would be using the same calculation for the DSR.
    I imagine they woukd have to using the same ...thats the point If i was looking, i wouks be trawling the USGA for info, they have always had a lot of the handicap info available. And possible do some searching on the 'pope of slope" the guy that invented the slope system has some extensive articles online. He may well have written more about the nsew system.
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    Email and ask the R and A

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    I just had a look on the handicap add and it lists as daily difficulty. In the 23 rounds it shows all have been 0 bar one that was +2

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    They do this by multiplying the numbers of balls bowled by the number of balls faced, and dividing that by the average age of the batting side, minus the number of spanners in a Sidchrome tool kit.
    Forum needs more banter.

  14. #14

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    Quote Originally Posted by sms316 View Post
    They do this by multiplying the numbers of balls bowled by the number of balls faced, and dividing that by the average age of the batting side, minus the number of spanners in a Sidchrome tool kit.
    😂😂😂 love the 12th man

  15. #15
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    Guys- its at this link https://www.golf.org.au/whs/

    It took me 30 secs to find.

    • The WHS will feature a statistical daily rating system. It will be called PCC (Playing Conditions Calculation).
    • The WHS daily rating formulas and regulations have been in full effect in Australia since May 2019.
    • The PCC will be displayed on your handicap record as an adjustment value (eg ‘+2’ or ‘-1’) rather than a value such as ‘68’ or ‘72’ which happened pre-WHS under the Australian DSR system.
    • PCCs are permitted to range anywhere between -1 (ie easier conditions) and +3 (harder conditions).
    How does the Playing Conditions Calculation (PCC) system work?

    Under the PCC system, GOLF Link assesses a current course rating adjustment for you each day. This adjustment value is appropriate to the conditions you actually experienced. GOLF Link does all of the work and provides the PCC immediately after the scores are processed. Through GOLF Link, the PCC system establishes:
    • The expected average Stableford score for each player in the competition, based on their Daily Handicap; and
    • The actual Stableford score for each player in the competition.
    Then GOLF Link establishes the proportion of players who scored below expectation by one, two, three, etc Stableford points and similarly for those who scored above expectations.
    • Using statistical concepts, it is possible to determine from these proportions the likely level by which the conditions were different from what is normal.
    • The greater the field size, the more likely it is that a given level of variation in scores will lead to the conclusion that the variation is beyond normal random movements.
    • The PCC formulas are quite conservative – the PCC value will only be different to zero if the scores clearly suggest then an adjustment is warranted. (18-hole PCCs will always be whole numbers. 9-hole PCCs are permitted to range anywhere between -0.5 (ie easier conditions) and +1.5 (harder conditions); 9-hole PCCs can have decimal values of ‘.0’ or ‘.5’.)
    Does the PCC system require any work by clubs?

    No. GOLF Link does all of the work. It provides the PCC value immediately after the scores are processed.
    Why do we need course ratings?
    • The objective of a course rating system is to enable us to standardise scores.
    • A gross score must first be standardised before it can be used for handicapping.
    • Standardisation enables us to meaningfully assess the value of a score, and to meaningfully compare it with all other scores. For example, is 78 a good score? In order to answer that question we need to know the difficulty of the course. (For example, 78 from the championship tees at The Australian Golf Club is a much better achievement than 78 on a par 3 course.)
    • Course ratings are intended to precisely measure the difficulty a course presents to a golfer in the playing of their round.
    • If the rating of a course is not a true reflection of the difficulty it presented to a golfer in the playing of a round, the player’s standardised score for that round will be inaccurate. If the standardised score is inaccurate, the player’s handicap will be distorted (ie if inputs are inaccurate, so must the output also be inaccurate).
    • For this reason, every set of tees on every golf course has a Scratch Rating assessed for it by a group of State/Territory experts.
    What is the benefit of assessing each day whether any adjustment of the Scratch Rating is warranted to account for abnormal playing conditions?
    • We all know that the difficulty of a golf course can vary substantially from day to day. Daily fluctuation can be caused by changed hole placements, varying green speeds & green firmness, and changed weather.
    • With the vast majority of Australia’s golfers playing in coastal cities that are prone to variable weather conditions, it is particularly important for Australia to have a handicap system that is sufficiently flexible to cater for daily movements in playing conditions. If we don’t, we end up processing scores against inaccurate ratings, and that makes handicaps inaccurate.
    • PCC leads to more stable and comparable handicaps than if the vagaries of fluctuations in conditions from day to day and season to season prevail.
    What role in the handicap system does PCC actually perform in the calculation of a handicap?
    • A player’s gross score is compared against the PCC-adjusted Scratch Rating value in order to determine a player’s ‘Raw Score Differential’ for that round. (The ‘Raw Score Differential’ is displayed in a player’s handicap record on www.golf.org.au).
    • PCCs are NOT used to retrospectively adjust the results of a competition that has already been played. When reading out competition results, if a player had 40 points, the Captain would announce that the player had 40 points (irrespective of the PCC).
    • PCCs are NOT used to retrospectively adjust the Daily Handicap that a golfer played off in a competition that has already been played. When reading out competition results, if a player played off a Daily Handicap of 23, the Captain would announce that the player played off a Daily Handicap of 23 (irrespective of the PCC).
    Can the PCC strategy be summarised in one paragraph?
    PCC helps to provide golfers with a rating that is a reflection of the conditions they played under. The formulas determine whether the difficulty presented at the time by the playing conditions was normal or different to normal.

  16. #16

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    Thanks @BUSHY I have seen that link and while it does explain the concept, it doesnt provide what those statistical formulas are that are actually used in the PCC calculation.

    Edit: fixed some typos.

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    Last edited by Maxbxl; 27th February 2022 at 05:13 PM.

  17. #17
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    Quote Originally Posted by 4Puttpete View Post
    Email and ask the R and A
    Don't bother, all correspondence with the R&A regarding rules gets directed to Golf Australia.

  18. #18
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    Quote Originally Posted by Maxbxl View Post
    Thanks @BUSHY I have seen that link and while it does explain the con eot, it does. It provide what those statistical formulas are that are actually used in the PCC calculation.

    Sent from my SM-A515F using Tapatalk
    Roger that.


 

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