Playing Handicap Calculation

[rogolf]

I was referring to this post by antip, where it seems Golf Australia has just moved the 0.93 to a uniform allowance:

Here it is all done for you, in the whole country through a single website and database, for every competition player whenever/wherever they are playing in a club or open (not social) competition. At many clubs, the cards are issued by the club with the course handicap already on them, with the card print function linked to the database, which adjusts for the course slope, CR-Par, and the adjustment factor which in this country is universal at 93 per cent. If the competition doesn't print complete cards, the player just takes their handicap index and looks it up on a look up sheet in every proshop and on every notice board with that sheet turning the HI into the Course Handicap. Another alternative is to log in to the database and tell it which course you are playing and it will also spit out the answer. No-one does manual adjustments here ever.

RO asked why adjustment? In this country we started at 96 per cent and a few years back it got adjusted to 93 per cent and has stayed there through this WHS adjustment. The motivation was statistically based on trying to deliver what was perceived as more equitable outcomes in competition results across the handicap range. That was code for high handicappers carting off too much of the silverware.

[davep043]

Thanks, sorry for my confusion. Its interesting to me that we still see these (relatively small) differences in the handicap we use when we play. The Index is calculated the same everywhere now, but getting to our Playing Handicap (or Daily Handicap in Australia, I guess) is a little different. Its also interesting that in Australia, for instance, its the same multiplier for all formats, while in the US different formats require slight adjustments. I'm no statistician, I have no idea which method gives more equitable results, its just interesting.

[Newby]

There are two different formulae for calculating Course Handicap and the % allowances for use in Playing Handicap seem to be infinite.

However the use of the decimal in CH to arrive at PH is not an option (for the next few years at least)

[rogolf]

Your comments about the "why" of allowances are similar to mine in a post above. I haven't seen any statistical justification for them. Maybe Golf Australia's system is the best - make it the same for all forms of play. But then the system might just as well leave it in the calculation of handicap index so that nobody has to do onsite calculations and rounding.

Regardless, the "allowances" are only recommendations and not mandatory to use. I don't expect that they will be used in the leagues that I play in - too much fuss and prone to error.

[Newby]

It is universal. It should have been included in the draft between Clause 6.1 and 6.2 but was missed by CONGU.

The CONGU Technical Committee are taking it up with the R&A WHS people in the next few days on the grounds that it will be confusing and unpopular with players. I gather there is an expectation that unless it is in the front end software, it will be ignored by most players. The good news is that it will make no difference to handicap processing because neither PH nor CH play a part in the Score Differential. It may very occasionally affect a competition result.

But as the WHS people say (allegedly) 'WHS is about handicapping not competitions'

[Newby]

See my comment in the post above re Score Differential

[davep043]

I agree, I think it will be ignored for most play. I hope the Tournament Management software packages will do the calculations correctly when printing scorecards and evaluating results for competitions.

But that last quote surprised me, I've always felt that the primary purpose for a handicap system was to facilitate equitable competition. The wording in Rule 1.1 of the Rules reflects what must be a kinder gentler society, where competition isn't so important. The third of the stated purposes for the Handicap System is to give as many golfers as possible the opportunity to:

"Compete, or play a casual round, with anyone else on a fair and equal basis."

[rogolf]

I see it, but don't understand what you are trying to say about allowances.

[Newby]

Although allowances make a difference to a competition score they do not affect any adjustment to the handicap index as a result of the round.

[rogolf]

And, back to my questions - why are there any "allowances", ie, why aren't they all 100%? Where is the backup information for the recommendations? Shouldn't they be the same worldwide?

[nsxguy]

So the CH will be reduced by 5%.

So a CH of 20 will get 19.

A CH of 15 will get 14.

A CH of 10 or less not be reduced.

OK, I'm in. LOL

I pity the committeemen who will have to deal with all the competitors who WILL bother to check their own CH before the round and run to the committee to find out why it's a shot too low. LMAO

[Newby]

All national authorities have their own data (good or bad, strong or week). I suspect that this is one of the areas where concessions were needed to get the system over the line.

There are whispers that WHS will have some (hopefully all) variances eliminated before the revision in four years time. I understand there is now a sort of 'opt in/opt out' list that national authorities can switch at any time.

 

[antip]

As I said earlier, here one number (93 per cent in recent years) is used universally, all competitions and formats. Even Scramble type events (eg that total the team hcap and then apply a divisor) also cue off this one CH number that has already embedded the 93 per cent. Simple fact is, few golfers in Australia are even aware that the 93 per cent adjustment is happening.

The current description of this on the Golf Australia website is:

Why do we include a 0.93 multiplication in the calculation of a Daily Handicap? The 0.93 factor is called ‘the Multiplier’. The Multiplier is a balancing factor designed to offset the impact of players on different handicap levels having different levels of consistency. In general, skilled players are more consistent than less-skilled players, so if we didn’t have the Multiplier there would be a strong advantage for high-handicap players in handicap competitions.When we moved to Slope based a decade ago, that adjustment factor was 96 per cent, referred to as the "improvement factor". There was then statistical analysis of the competition results nationwide - bearing in mind this country boasts one single centralised massive database - and the statistical gurus concluded that equity in results for the way competition golf operates in this country supported changing that 96 to 93 per cent - and that number has again been confirmed in the context of WHS introduction assessments.

Edit PS addition: given the enormous cultural/behavioural differences revealed in discussions on this website in the way handicap-relevant scoring processes occur in the USA compared with here (for example gimmes, most likely score; degree of on course gambling, voluntary self declaration and so on) I can see arguments why one size does not fit all.

[rogolf]

So, it sounds like the former "reward for excellence" that was removed from the USGA system. I do agree that one "allowance" could be used for every format of play.

[Augster]

I hope the WHS goes to a full time .93 multiplier and does away with all the other nonsense.

In the US, we had 10/20 and the .96 multiplier. Now with WHS, we have gone to 8/20, but no multiplier. My index stayed the same.

A .93 multiplier full time, backed up by years of data arriving at that multiplier being most equitable for all forms of play, is a pretty strong reason to go to it. It’s not easy to play a guy straight up one day where his multiplier is 100%, then get in a foursome the next day and tell him that his multiplier is .85.

[antip]

Here the change from 96 to 93 was done at the same time as going from 10/20 to 8/20.

While Australia's data set supported/motivated this 96 to 93 change; it isn't obvious that our equity argument necessarily works for a different national data set, given the extent of cultural/behavioural differences.

The WHS factor that surprised many was moving the 93 per cent to the daily CH calculation - which meant everyone's HI rose by circa 7 per cent, but this has no practical relevance because it is removed again at the last stage now.

[Deceptively Short]

So does this mean that each jurisdiction will have different handicap allowances for different formats of play? I’d so, Isn’t this contrary to the aim of a unified system. Wouldn’t unification of this element be an easy fix?

Surely the justification of the handicap allowances is based on ‘fairness’ of competition which should be the goal of WHS.

[DaveLeeNC]

To me there are 2 different things that the handicap system does.

1) Take the range from scratch to a handicap of 56.0 - it establishes 561 ordered groups of people of 'equivalent scoring skill' (an imperfect result because it is an imperfect question). E.G., all players with an index of 11.6 are the same, all with an index of 27.5 are the same, etc.

2) Establishes a way to level play between 2 players in different groups.,

They are not the same thing and each one is a reasonable 'goal of the system' on its own.

dave

[Deceptively Short]

Surely the sole purpose of goal 1 in your post is to achieve goal 2.

Without goal two the need for achieving goal 1 is solely to put as accurate a number on a players ability, with the prevalence and ease of getting a ‘vanity handicap’ in some systems this is a futile exercise.

If not a means of giving ‘as level a playing field as possible’ for players to compete against each other then what is the purpose of handicaps?

[DaveLeeNC]

Some folks keep a handicap simply as a gauge of personal achievement on the course. That could include me in a year or two. dave

[Sawgrass]

"If not a means of giving ‘as level a playing field as possible’ for players to compete against each other then what is the purpose of handicaps?"

 

The Rules of Golf create the level playing field. The Rules of Handicapping's purpose is to create a somewhat random outcome to a game between two or more people that otherwise perhaps needn't even be played.

[davep043]

That's an interesting way to say it, "create a somewhat random outcome", but its not much different from the stated purpose, which includes:

" Its purpose is to enhance the enjoyment of the game of golf and to give as many golfers as possible the opportunity to:

Obtain and maintain a Handicap Index,

Use their Handicap Index on any golf course around the world, andCompete, or play a casual round, with anyone else on a fair and equal basis."

If a random outcome means that each player or team has a reasonably even chance of winning, and to me it does, I'm happy to agree.

[Newby]

The differences are few but CONGU has already changed its 4BBB allowance to 90% which brigs it into line.

However it may have been a typo in the original draft

[Newby]

England Golf has just announced that the Playing Handicap will be calculated from the Course Handicap, using the rounded value (no decimal).

CONGU intend to confirm and publicise in due course.

Seemingly they have used US experience where many golfers are using the whole number as they found it easier.

 

[rogolf]

And, seemingly, less precise.

[Sawgrass]

I have been told that the Golf Genius Tournament app (at least in the US) calculates allowances off the true decimal number. (But I have been misled previously by a different authority, so who knows until I can make my own calculation.)

[Newby]

Presumably precise enough given that slope isn't the most accurate calibration and par isn't necessarily consistent

[davep043]

It seems to me that this is a very simple calculation to program into any tournament management software, but I understand is slightly less simple when done by individuals who are presented with a pre-rounded Course Handicap. As you quite correctly say, the whole thing is somewhat arbitrary, and the differences caused by rounding twice instead of just once are at most a single stroke to a small number of players. If I were the one making decisions, I'd probably make sure it was done correctly (rounded at the very end) for formal competitions, while accepting that for less formal situations it will be done slightly wrong. I'd also ask my app developers to add in some way to select "Competition Format" so that it would be dead simple for anyone to get it right. Its probably a good thing that I don't actually make all of these decisions, I'm sure I'd screw up in some huge way.

[rogolf]

I'm not buying that "close enough is good enough". If precision in the final calculation isn't that important, why is there so much attention to precision in all the preceding calculations?

[Newby]

Why is slope a straight line when is has been demonstrated that at various points it is inaccurate? Why are Australia using 0.93 and others using 0.95 or 0.90?