Help me understand my Score Differential!

[IanM]

Another thread demonstrating that as soon as you think you understand something, there's something else deep in the manual/the maths/waste paper bin in St Andrews that you've missed.

Best just forget it all, play golf and the only number to look on at the App at is HI.

Your adjusted gross of 82 would trigger an exceptional scoring reduction of 2, which has been applied to all the earlier differentials, hence the apparent discrepancy.

So, for the sake of clarity. If a cap, or and ESR has been applied, it adjusts all the early differentials, so comparative analysis of earlier score wont work? Are there other things that have the same effect?

 

[peld]

Your adjusted gross of 82 would trigger an exceptional scoring reduction of 2, which has been applied to all the earlier differentials, hence the apparent discrepancy.

why would it?
it'd cut his HCP index by more after that round, but ive seen nothing that would say it'd historically cut all historical scores?

"A score differential which is at least 7.0 strokes or more better than the player’s Handicap Index at the time the round was played.
Score can be from any format of play, competitive or general play and this is not restricted to competition scores.
When a player submits an exceptional score, the handicap formula applies an additional adjustment to the player’s updated Handicap Index.
This adjustment is in addition to any reduction caused within the 8/20 calculation.
The Handicap Committee can override the adjustment if they deem necessary."

 

[Swango1980]

Your adjusted gross of 82 would trigger an exceptional scoring reduction of 2, which has been applied to all the earlier differentials, hence the apparent discrepancy.

Indeed, that is the answer to the question.

Would have been helpful if the scoring history had an additional column for "Adjustment" to show the -2.0

 

[Mshcah]

I think that might be the answer! Thanks to everyone who helped me sort this out.

 

[Swango1980]

why would it?
it'd cut his HCP index by more after that round, but ive seen nothing that would say it'd historically cut all historical scores?

"A score differential which is at least 7.0 strokes or more better than the player’s Handicap Index at the time the round was played.
Score can be from any format of play, competitive or general play and this is not restricted to competition scores.
When a player submits an exceptional score, the handicap formula applies an additional adjustment to the player’s updated Handicap Index.
This adjustment is in addition to any reduction caused within the 8/20 calculation.
The Handicap Committee can override the adjustment if they deem necessary."

You just quoted in italics the answer to your question. It provides an additional cut to your Index of 2.0.

How does it do that? Well, given that your index is mathematically the average of your best 8, the only way it can mathematically cut your Index down by 2.0 is to reduce all your previous scores making up your top 8 by 2.0 as well (so it simply applies this to all previous 20 scores). Once it does that, you get that 2.0 exceptional reduction.

 

[wjemather]

why would it?
it'd cut his HCP index by more after that round, but ive seen nothing that would say it'd historically cut all historical scores?

"A score differential which is at least 7.0 strokes or more better than the player’s Handicap Index at the time the round was played.
Score can be from any format of play, competitive or general play and this is not restricted to competition scores.
When a player submits an exceptional score, the handicap formula applies an additional adjustment to the player’s updated Handicap Index.
This adjustment is in addition to any reduction caused within the 8/20 calculation.
The Handicap Committee can override the adjustment if they deem necessary."

Rule 5.9
"A reduction for an exceptional score is applied by adjusting each of the most recent 20 Score Differentials recorded in the player’s scoring record, which includes the exceptional score."

 

[Backsticks]

Indeed, that is the answer to the question.

Would have been helpful if the scoring history had an additional column for "Adjustment" to show the -2.0

I agree. There is a touch of rewriting history without even noting that it has been done, the way it is shown at the moment. I had similar : two 1 shot exceptional reductions applied about 6 weeks apart, so now have some differentials correct since the second one, some that have a 1 reduction applied to them, and others that have the 2 reductions applied. So the original differentials are well disguised at this stage. And not really comparable as a group any more.

 

[wjemather]

So, for the sake of clarity. If a cap, or and ESR has been applied, it adjusts all the early differentials, so comparative analysis of earlier score wont work? Are there other things that have the same effect?

Caps do not affect the SDs; only adjustments (including ESRs) do that. Any analysis just needs to take these adjustments into account - I'm not sure if it's only the app where they are not shown.

 

[IanM]

There you go then... Fairly sure that is different from the earlier conversation, when my wife's handicap was capped. But no matter.... as I said, this wasn't designed for folk to interrogate, just to use.

 

[peld]

it seems silly to adjust the historical scores rather than just reflect the overarching -2 adjustment

 

[wjemather]

it seems silly to adjust the historical scores rather than just reflect the overarching -2 adjustment

By directly adjusting the SDs, the effect of any adjustment(s) slowly filter out over the course of the next 20 scores. Using any other method would be significantly more complicated.

 

[Swango1980]

it seems silly to adjust the historical scores rather than just reflect the overarching -2 adjustment

why? The index is a mathematical calculation. If you just took 2 off the index, the average of the best 8 calculation would simply be wrong. Furthermore, you run into problems when you continue to submit scores. When do you remove the -2.0 reduction, or does it remain forever? By applying it to the previous scores, it gives the -2.0 to your current index. It is not applied to the score diff of future scores, so the impact of the -2.0 is gradually reduced, and ultimately gone once the older scores drop outside your last 20 scores.

 

[Backsticks]

By directly adjusting the SDs, the effect of any adjustment(s) slowly filter out over the course of the next 20 scores. Using any other method would be significantly more complicated.

Yes, its a clever and fair way to apply it alright. It just could be highlighted to make it clearer for those who follow the hc evolution.