course handicap calculation

[andrewfulton]

Someone plays off 23.5 the slop of the course is 132

So 23.5x132/113 = 27.45132

My questions is one of rounding, there are a number of documents which say when doing a handicap calculation you do it to 1 decimal place…..

If you calculate this formula to one decimal place on a spreadsheet it comes to 27.5 which then if you round to a course handicap it round to 28

But on 2 of the popular apps it returns a course handicap of 27.....

So i assume those APPS are taking the 27.45132 and moving it to 27.4, which rounds to 27

Which is correct.......

Thanks

 

[Neilds]

I would say that 27 is correct as the spreadsheet has displayed the answer to 1 dp and not calculated it. If you change the settings on the spreadsheet to increase to DP shown it will still give a longer number

 

[jim8flog]

Where you round depends on which country you are

Within the Rules of Handicapping you round .4 down and .5 up

Rule 6.1

Note: The calculated 18-hole and 9-hole Course Handicap is rounded to the
nearest whole number, with .5 rounded upwards, for the purpose of:

Where applicable, calculating a Score Differential.

 

[andrewfulton]

i understand rounding. .4 goes down .5 goes up.....

but its how do you arrive at a single decimal point from the caluclated 27.45132, surely to get to a single decimal point you go to 27.5 which then rounds up to 28 , which is not what these apps do......

 

[Foxholer]

I've just entered those numbers into a club's calculator - that allows Slope to be manually entered and that returns CH of 27/PH of 26
I expect the 'rounding' is actually involves a 'chop' of 2nd and further decimal places. So n.5 rounds up, while n.49 rounds down.

 

[andrewfulton]

it seems there must be a chop done before it gets to the 1 decimal..... i just cannot find this is any documentation on the topic.....

 

[Deleted member 15717]

Which apps show 28 being the CH?

its one decimal place, so 27.4 is the taken number. anything after the .4 is disregarded so you dont round the .4 to .5

i believe Scotland go to 2 dp….maybe to factor in this rounding?

 

[wjemather]

Someone plays off 23.5 the slop of the course is 132

So 23.5x132/113 = 27.45132

My questions is one of rounding, there are a number of documents which say when doing a handicap calculation you do it to 1 decimal place…..

If you calculate this formula to one decimal place on a spreadsheet it comes to 27.5 which then if you round to a course handicap it round to 28

But on 2 of the popular apps it returns a course handicap of 27.....

So i assume those APPS are taking the 27.45132 and moving it to 27.4, which rounds to 27

Which is correct.......

Thanks

One decimal place (phrased as "rounded to the nearest tenth" in the rules) applies to the Handicap Index and Score Differential (and Course Rating), but not Course Handicap.

For Course Handicaps, the rules and CONGU's guidance refer only to "rounded to the nearest whole number", "rounded integer" and "full calculated" (unrounded) values.

For clarity, in Scotland, 3 decimal places are used wherever "full calculated" applies (i.e. Playing Handicap calculations) since any further accuracy is unnecessary. The rest of GB&I use the rounded integer value.

The apps are doing the calculation correctly by simply using the full calculated value to produce the rounded integer value.

 

[Voyager EMH]

 

[Swango1980]

i understand rounding. .4 goes down .5 goes up.....

but its how do you arrive at a single decimal point from the caluclated 27.45132, surely to get to a single decimal point you go to 27.5 which then rounds up to 28 , which is not what these apps do......

In Scotland, Course Handicap is to one decimal place, so the answer is 27.5

In the rest of the UK, it is to a whole number. So, the correct answer is 27. It is not 28, because to get 28 you are effectively choosing to round up 27.45132 in two stages (firstly to 27.5, then to 28), when you should only need one stage to round the first number.

 

[wjemather]

In Scotland, Course Handicap is to one decimal place, so the answer is 27.5

Where are you getting this from?

(Rule 6.1) Course Handicap is rounded to the nearest whole number for all practical purposes (ndb adjustments, dnp adjustments, score diff calculation, etc.), except where the full calculated value is retained for Playing Handicap calculation purposes (per appendix I of the Scottish version of CONGU's guidance, for practical purposes this is 3 decimal places).

 

[Swango1980]

Where are you getting this from?

(Rule 6.1) Course Handicap is rounded to the nearest whole number for all practical purposes (ndb adjustments, dnp adjustments, score diff calculation, etc.), except where the full calculated value is retained for Playing Handicap calculation purposes (per appendix I of the Scottish version of CONGU's guidance, for practical purposes this is 3 decimal places).

Yeah, my wording was clumsy. I was trying to demonstrate rounding to one decimal place would be 27.5, and rushed in to use Scotland as the example, were playing handicap is made from a course handicap that is not a round number. However, of course it is not rounded at all, not even to one decimal place.

 

[jim8flog]

I would use the simple assumption based upon calculation of a handicap index.

The calculation of a H.I. removes the values after the first decimal place so it follows that those in charge of the 'official'* calculation of course handicap would do the same.

* ISVs, England or other Area Authority app or the WHS platform

 

[nickjdavis]

i understand rounding. .4 goes down .5 goes up.....

but its how do you arrive at a single decimal point from the calculated 27.45132, surely to get to a single decimal point you go to 27.5 which then rounds up to 28 , which is not what these apps do......

No....maths doesn't work like that. You simply truncate the digits after the 4.

Think about it logically....it is obvious that 27.45 is less than half way between 27 and 28, so that simply does not make logical sense to use the 5 (hundredths) to round the 4 (tenths) up to 5 and then use this to round the 27 up to 28.

 

[Steve Wilkes]

No....maths doesn't work like that. You simply truncate the digits after the 4.

Think about it logically....it is obvious that 27.45 is less than half way between 27 and 28, so that simply does not make logical sense to use the 5 (hundredths) to round the 4 (tenths) up to 5 and then use this to round the 27 up to 28.

27.499999 is 27, 27.5000 is 28, 27.500001 is 28

 

[IanM]

Why bother?

Just look at the tables by the tee! , or the Wales Golf App tells you! I assume the other apps do same.

 

[andrewfulton]

One decimal place (phrased as "rounded to the nearest tenth" in the rules) applies to the Handicap Index and Score Differential (and Course Rating), but not Course Handicap.

For Course Handicaps, the rules and CONGU's guidance refer only to "rounded to the nearest whole number", "rounded integer" and "full calculated" (unrounded) values.

For clarity, in Scotland, 3 decimal places are used wherever "full calculated" applies (i.e. Playing Handicap calculations) since any further accuracy is unnecessary. The rest of GB&I use the rounded integer value.

The apps are doing the calculation correctly by simply using the full calculated value to produce the rounded integer value.

Thanks where can i find the official "the rules and CONGU's guidance" you refer to above

 

[wjemather]

Thanks where can i find the official "the rules and CONGU's guidance" you refer to above

They are available to download from the websites of the home unions (for some reason they are no longer available from CONGU's website):

• Rules of Handicapping
• CONGU's Guidance on the Rules of Handicapping (Eng/Wal/Ire)
• CONGU's Guidance on the Rules of Handicapping (Sco)

 

[Deleted member 30522]

Thanks where can i find the official "the rules and CONGU's guidance" you refer to above

https://scottishgolf.org/handicapping-homepage/world-handicap-system/

 

[Swango1980]

Looks like BB has wjemather on ignore then