Trying to understand the WHCP graph

[albie999]

I have started to register my rounds with the app for the World Handicap Golf System, that I need to use (Wales Golf App), however, I am slightly confused by the graph that they are presenting.

I kinda get what the green line is, however, do not understand the other line and how they relate to each other. I have looked on the help section of the app, but the description just seems to totally confuse me

Any help understanding this is appreciated

 

[SwingsitlikeHogan]

I don’t think it’s possible to fully correlate the two lines. The two lines simply show the history of your scoring and HI. So for instance a counting score will generally impact your HI by reducing it, unless the counting score being replaced was your 20th, in which case your HI could go up rather than down.

I am guessing that the slight/minor up and down variations between scores (points on the curves) that seem inexplicable will be down to the mathematical order of polynomial (curve) used to fit a curve through the points defined by your scores…the variations are not real variations in your HI - they are a function of the mathematical curve fitting…well that’s my guess.

 

[Neilds]

The 2nd line (with yellow and orange dots) is your score. Not exactly sure what the scale is on the vertical axis, may be score over par or score differential but either way the lower the dot, the better on that line.

Hopefully this is easier to understand that SILH's maths lesson

 

[albie999]

Thanks both, it looks like the score, is the score differential, which again might need a lesson on that ... I presume is the difference between my score .. say, I went round in 90, and what the course rating is .. say 72 PAR, the score differential would be 22 .... Or have I got that completely wrong?

 

[Neilds]

Score differential indicates the Handicap Index that has been 'played to' for a round on a specific course on a specific day

 

[rulefan]

PAR is not necessarily the Course Rating.
But the Score Differential is
(Gross Score (adjusted for any net double bogeys) - Course Rating) x (113/Slope Rating).

 

[albie999]

Score differential indicates the Handicap Index that has been 'played to' for a round on a specific course on a specific day

Ok, so in my case for the screenshot I provided .. I was playing off a HCP index of 24.4 (for that round) .. but I played to a HCP level of 21.9 (therefore under HCP)?

 

[rulefan]

What was your Gross Score, Index, Course Rating and Slope of the course on that day? Did you have any scores over net double bogey?

 

[albie999]

What was your Gross Score, Index, Course Rating and Slope of the course on that day? Did you have any scores over net double bogey?

This was the card:

 

[Neilds]

Ok, so in my case for the screenshot I provided .. I was playing off a HCP index of 24.4 (for that round) .. but I played to a HCP level of 21.9 (therefore under HCP)?

Yes, you did

 

[SwingsitlikeHogan]

…and if I am right the clever maths simply makes the lines look a bit sexier than simple straight lines joining the points defining HI and Round Differential, and, as a result, in between the points of each curve the curves are inaccurate of not meaningless.

 

[Alan Clifford]

…and if I am right the clever maths simply makes the lines look a bit sexier than simple straight lines joining the points defining HI and Round Differential, and, as a result, in between the points of each curve the curves are inaccurate of not meaningless.

Only the points are meaningful as the data is not continuous, and does not even exist, between the points.

The yellow dots are the 8 out of the last twenty differentials that are included in your current handicap index.

 

[SwingsitlikeHogan]

Only the points are meaningful as the data is not continuous, and does not even exist, between the points.

The yellow dots are the 8 out of the last twenty differentials that are included in your current handicap index.

Yes indeed. But a set of discrete points does not an interesting graph make…and straight lines look a bit clunky, so let’s make a sexy curve ? That said - once we have 20 plus rounds any curve will tend towards being a pretty good fit - indeed straight lines between points will tend to such a curve. Doesn‘t make anything on any curve between points any more meaningful though.

 

[Alan Clifford]

Yes indeed. But a set of discrete points does not an interesting graph make…and straight lines look a bit clunky, so let’s make a sexy curve ? That said - once we have 20 plus rounds any curve will tend towards being a pretty good fit - indeed straight lines between points will tend to such a curve. Doesn‘t make anything on any curve between points any more meaningful though.

I use straight lines.

 

[jim8flog]

I have started to register my rounds with the app for the World Handicap Golf System, that I need to use (Wales Golf App), however, I am slightly confused by the graph that they are presenting.

I kinda get what the green line is, however, do not understand the other line and how they relate to each other. I have looked on the help section of the app, but the description just seems to totally confuse me

Any help understanding this is appreciated

View attachment 43813

At the moment you only have 6 scores on your record so your Handiicap Index is the average of the best 2 minus one shot

The line with red and yellow dots are your actual differentials. The red dots (non counting) are scores not used in the calculation and the yellows ones (counting) are the 2 used in the calculation. as you add scores red dots may change to yellow ones as more and more scores are used in the calculation.

Ongoing