How is CSS calculated?

This isn't a thread about how unfair it is just a genuine query.

A couple of weeks ago our club held a winter stapleford. As the course had some winter greens it wasn't a qualifier but it was frozen so also pretty tough. The winter par is 69 but the CSS was 68. What I thought was odd about this was that out of the 30 players only one broke his handicap (38 points of HC 13), one matched then everyone else was below with scores from 22 up. 7 were within 3 of their handicap. The spread of handicaps was from 2 to 22 with 15 players in the 12-16 HC range. If it makes any difference two of the lower HC players scored 27 off 2 and 10.

I know that there is some sort of complicated formula done but I thought that it was roughly something along the lines of how many players broke net par which wouldn't seem correct here.

Dunno how it works but CSS at our place is less than SSS far more often than it is above SSS. If you ask me, it's a made up algorithm which doesn't stand up to much scrutiny.

Would be interested to know the actual calculation though...

I would love to know how CSS is calculated in lehman terms. Simply because when i've looked it up on the CONGU website it's like trying to wade through glue.

The amount of times I see the CSS at our place set to -1 or -2 yet see the lion share of the scores are above even what SSS is makes me scratch my head. There's been several occurences where I can't fathom why I've not had a bigger cut or seen others go up .1 when looking at it should have remained as they were.

navyblueshorts wrote:Dunno how it works but CSS at our place is less than SSS far more often than it is above SSS. If you ask me, it's a made up algorithm which doesn't stand up to much scrutiny.

Would be interested to know the actual calculation though...

There was a new version of the CONGU UHS this year.
http://www.englishgolfunion.org/shared/get-file.ashx?id=8408&itemtype=document

See Appendix B

throw away the cat4 scores. then calculate the percentage of remaining players within +2 of SSS

Look that percentage up in a secret table and that tells you the CSS adjustment

i once played in a comp where the winner was 7-under par net but the CSS went up because he was cat4 and few of the cat1-3 players got close

We've had this discussion before. CSS can never be more than 1 below SSS but can go up by 3, more than that and it becomes a "non counting qualifier" meaning that cuts apply only: no 0.1s back.

In the hypothetical event that the whole field of Cat 1 to 3 shot 2 over par, the CSS would be SSS-1!

Asked this question a couple of weeks ago after hearing the system was changing for 2012. It seems that CSS will now be SSS plus your handicap category buffer zone ie +1 for cat 1 +2 for cat 2 etc. Am confused about this as it takes no account of conditions etc on the competition day - and it may even be an overly simplified explanation, but it's the best I have been able to get. In theory makes SSS more important.

Puligny

I believe that the change is that instead of the critical factor being the number of those players in Cats 1 to 3 within 2 shots of SSS setting the CSS it will now be those players in Cat 1 within 1 of SSS, plus those in Cat 2 within 2 of SSS, plus those players in Cat 3 within 3 of SSS. The tables will still apply. The thinking is that it should mean that the CSS will not go down quite as often as before - which to my mind is a good thing.

In practice, I think that CSS is less likely to go below SSS on any given competition day. In theory though, if lots of players had a field day, I can't see why the CSS couldn't be 2 or even 3 less than SSS.

The way handicaps are calculated (ie from this complicated algorithm) means that most players don't play to their handicaps most of the time. For example, a guy who plays off 10.0 might play to that or better 25% of the time, and worse than that 75% of the time. So on any given day, in reasonable conditions, you could reasonably theorise that only 25% of the field plays to their handicaps or better. That's roughly what most clubs see in most competitions.

There are occasions though, usually on nice warm days, with no breeze and the course dry with plenty of run, that many more people score well. I haven't studied that CONGU 2012 thing but those would be the days when the CSS could be less than SSS -1.

I never seem to play a competition in nice conditions these days - it's always windy and the course is wet, even if it's not raining.

George

CSS cannot go down more than 1 below SSS. That's what the handicap system stipulates. It can only go down by 1 but up by 3.

This all seems absurdly complicated. What's wrong with taking an average of the whole field and then a few people charged with doing so consider the possible impact of course set-up, ground conditions and weather???
End result probably a lot more representative of what players experience on the day.

Guys

Thanks for all the info. It is as complicated as I imagined but I think I have now got the jist of it.

The theory of it is how hard the course is on the day seems to be the basis then overlaid with how many players come within the buffer zone of their HC. This is then compared with what is considered an expected amount according to their categories. If more than expected for that level then the course is deemed to be playing easy.

The only part I am not sure about is whether one category has more influence than another.

Cat 4 players have no influence.

I bet there were Maths degrees written about how the equation came about. I am sure its up there with the Duckworth Lewis calculation. Basically a pretty simple idea but then applied science to it.

One thing it does answer is the often asked question of how often you are expected to hit your handicap. Over the years I have heard many different ones. Most common is 1 in 3 rounds. It appears that I am 23-45% likely to fall in my buffer zone.

Another thing that was answered in the handicap bible is that someone with a really low score influences the CSS. In fact someone scoring a net 64 has the same influence of someone scoring a net 73 (+3) in Cat 3.

The current system is fair and probably the changes for 2012 are designed to make it even fairer. However, like any system it's not perfect and can never be so.

Why scores within buffer and not scores breaker or playing to handicap?
Plot net scores on a graph (x-axis is net scores to SSS and y-axis is % of each score) and we all get a bell curve. Calculating the percentage that play within the buffer increases the sample and makes the measure more reliable. The percentage values used in the tables are increased to compensate. Reducing scores to SSS and less and decreasing the percentages for the table will over a season give the same average result, but there will be far more weeks when the CSS is simply wrong.

Minimum 1 Less
There may be the some days when the greens are perfect, the tees are up, the suns on your back, no wind, the rough has just been cut, the fairways are running, the greens are stopping, the pins are in easy locations and your playing with Jim and Bob who just get on with it and don't talk about the wife or the kids or work............ and on these days the course can play 2 or 3 shots easier, but these days are veryvery few (espacially in Scotland). If the SSS could come down by more than 1 then there will be occassions when a few extra guys shoot the lights out and everyone suffers.
A maximum of 1 shot is enough.

Bias to Lower Cats
Two reasons here me thinks. Firstly, lower handicapers scores will better reflect the true playing conditions on the day and secondly it is more important that the handicap system is calibrated for the lower handicappers. For example there is no difference between a 18 or 19 handicapper, but there is often a difference between a scratch or 1 handicapper. A 19 handicapper will get cut to 18 or even 17 for one good score, but a 1 handicapper will normally need 5 or 6 good scores to get down to scratch.

Stop moaning. The old system meant the CSS never changed so breaking your handicap meant both playing well and playing on the right day at the right time. The new system is a massive, massive improvement.

Going back in the day before this I can recall the lower handicappers pitching up for a medal looking at the wind and weather and deciding not to bother to protect their handicaps.
2012 rules should work better must be progress

I know what you mean, but it's not a bell curve is it? If you assume stableford scores, then the top of the curve will be about 35 points, but the curve will be a sort of wedge of cheese shape because for every score better than 36, there'll be ten or more worse than 35. So if the x axis starts with (say) 18 points, and goes up to the winning score of 42, the curve will climb steadily to 35 (the median) and then quickly plummet back to the axis again afterwards.

I'm sure there's some statistician out there that knows what shape that is - piece of cheese isn't very scientific. What's a hyperbolic parabaloid? Some neurons sparking here that haven't seen any activity since I did my O grades...

ScottieD18 wrote:...Stop moaning. The old system meant the CSS never changed so breaking your handicap meant both playing well and playing on the right day at the right time. The new system is a massive, massive improvement.

Thanks for the breakdown. Not convinced you're correct but as I'm not a statistician...

As for moaning, I don't care if on average, CSS is more accurate over a year if it makes a mess of a single round where I'm to handicap or +1, which is the buffer in my category. I don't mind the reduced CSS on a 'good' day but it's dropped far more than it goes up; in fact, it almost never goes up. It isn't a good representation of anything IMO. Then again, maybe those doing the maths and consulting tables at my place stuff it up a lot.

We have to remember that the change to using the 1, 2 and 3 shot buffers have only just been introduced. Last season it was a blanket 2 shots. So it's a bit early to assess what difference it is making?

Golfermartin - many thanks, that begins to make more sense.