Not a fan of GHIN new 9 hole scoring system

[iacas]

11 hours ago, Imp said:

A good 9 hole score is being penalized by automatically assigning the back as always an/the average.

 

First, it's not being "penalized" because you're still going to end up with a lower differential than your average.

 

Second, the USGA has a HECK of a lot more data on this than anyone posting here, and I imagine (like when people were complaining about the move to 8/20 from 10 and ditching the 96% bit) that it's not going to be as big of a change for the vast majority as the prognosticators like to think.

 

Who will it affect the most? People who play only nine-hole rounds.

 

Most golf tournaments and events are 18 holes. So, those nine-hole players aren't really establishing a "true" index anyway, so I don't see it as a big deal if it's not perfectly representative. Also, I bet it's more realistic than many here think.

 

But the USGA isn't going to (nor should they have to) share that data.

 

11 hours ago, Imp said:

I would think there should be more weight on the calc if having a good 9 on the front, the back 9 should reflect it.

 

People shoot 39 44 all the time.

 

11 hours ago, Imp said:

That one doesn't know how it would have turned out without having played it is my biggest issue.

 

If you want to know how it would turn out, play the other nine.

 

They've given their reasons for switching to this, and sometimes I had nine-hole rounds played months and months apart, on different courses, with completely different conditions. Is that more accurate than this?

 

11 hours ago, Imp said:

I could have blown up, I could have had an average round.

 

And those would average out to… about average.

[Imp]

Quote

First, it's not being "penalized" because you're still going to end up with a lower differential than your average.

Not true. Shot lower than my CH. Index was 10.1. Differential was 10.1. 

Quote

Who will it affect the most? People who play only nine-hole rounds.

 

Most golf tournaments and events are 18 holes. So, those nine-hole players aren't really establishing a "true" index anyway, so I don't see it as a big deal if it's not perfectly representative. 

 

Thank you for helping drive MY point/argument home - whether you realized it in your hubris or not.  The 9 hole calculation is flawed and should be re-worked since, as you say...  one "isn't establishing a true index anyway". (Your words, not mine). 

 

 

Edited May 13, 2024 by Imp

[davep043]

11 hours ago, iacas said:

First, it's not being "penalized" because you're still going to end up with a lower differential than your average.

 

26 minutes ago, Imp said:

Not true. Shot lower than my CH. Index was 10.1. Differential was 10.1. 

You DO realize your Index is the average of your BEST scores, and its lower than the average of ALL of your scores, right?  When you shoot your index, that's better than an average score, typically by 2 to 4 strokes.

 

[DaveLeeNC]

12 minutes ago, davep043 said:

You DO realize your Index is the average of your BEST scores, and its lower than the average of ALL of your scores, right?  When you shoot your index, that's better than an average score, typically by 2 to 4 strokes.

 

 

The issue is whether or not your best 9 combined with an estimated average score represents your best 18 hole score(s). I don't know the answer but I do question what a handicap record of only 9 hole scores really represents. I just don't know but I am not convinced that this answer is the one. 

 

dave

[davep043]

5 minutes ago, DaveLeeNC said:

 

The issue is whether or not your best 9 combined with an estimated average score represents your best 18 hole score(s). I don't know the answer but I do question what a handicap record of only 9 hole scores really represents. I just don't know but I am not convinced that this answer is the one. 

 

dave

I think that's a fair question, and one which will be different for different players.  I was merely fact-checking @Imp.  A better than average 9 hole score will yield a better than average 18 hole entry for handicap.  It won't be as much better as if the player had TWO of those same 9-hole scores combined, but its still better than average.

[st1800e]

On 5/12/2024 at 10:19 AM, DaveLeeNC said:

 

The official guidance here is to post "par plus strokes" on the unplayed holes.  See 

 

 

dave

This gets complicated.  I’ll post the complications in the quoted thread, as it’s more applicable to this. 

[jonflesh]

The new 9 hole policy does make it much tougher. I started the year at a 4 and now I’m a 7. I don’t see any real way to lower it unless I have some ridiculous rounds. I mainly play 9 because I play after work. 
 

i shot 38 today on a par 36 that is rated 35.5/136 and it computes at a 7.1. 
 

the hardest part is because the vast majority of my rounds are 9 holes it also drops the 18 hole rounds off at twice the rate it would have last year since we aren’t combining the 9 hole rounds anymore and each is its own entry. So even if I play some good 18 hole rounds they are gone really quick since I typically play 4-5 9 hole rounds a week

[North Butte]

8 hours ago, jonflesh said:

The new 9 hole policy does make it much tougher. I started the year at a 4 and now I’m a 7. I don’t see any real way to lower it unless I have some ridiculous rounds. I mainly play 9 because I play after work. 
 

i shot 38 today on a par 36 that is rated 35.5/136 and it computes at a 7.1. 
 

the hardest part is because the vast majority of my rounds are 9 holes it also drops the 18 hole rounds off at twice the rate it would have last year since we aren’t combining the 9 hole rounds anymore and each is its own entry. So even if I play some good 18 hole rounds they are gone really quick since I typically play 4-5 9 hole rounds a week

Honestly, it's almost like the new method was designed to annoy or punish people for posting a lot of 9-hole rounds. Surely that wasn't their intent but it's an undeniable side effect.

[iacas]

2 hours ago, North Butte said:

Surely that wasn't their intent

 

I mean, it's not like you can't go find and read exactly what their intent was, right?

 

The USGA has a heck of a lot more data on this than the collective data of anyone posting here.

[davep043]

12 hours ago, jonflesh said:

i shot 38 today on a par 36 that is rated 35.5/136 and it computes at a 7.1. 

And 7.1 is 2 or 3 strokes below "average" for someone with a 7 index.  

 

4 hours ago, North Butte said:

Honestly, it's almost like the new method was designed to annoy or punish people for posting a lot of 9-hole rounds.

In what way does it "punish" anyone?  Most of the detractors hate that a "good" 9 holes doesn't become a "great" 18 holes, but in the old system there was no guarantee that a good 9 was paired with another good 9.  In fact, I'd be willing to bet that the odds were strongly against that happening.  Also consider someone who plays 9 infrequently, and has a strong seasonal variation in handicap.  Combining 9 from today with 9 from a couple months ago could lead to a highly mis-representative combined 18.  At least now your "second 9" score will be based on your current handicap level.  Yes, its a change, and yes, it will impact some folks' handicaps, but its in no way a punishment.  The USGA (and CONGU and EGA and Golf Australia and all the rest) are NOT out to get you.

[jonflesh]

59 minutes ago, davep043 said:

And 7.1 is 2 or 3 strokes below "average" for someone with a 7 index.  

 

 

I understand it’s below my average. I’m not saying the new system is “unfair” but it is unquestionably harder to lower the handicap. If a 7 is more representative of my actual skill than the 4 I had prior to the change then so be it. 
 

But the new system effectively takes a really low round out of play for me. If I were to play on a Monday and shoot 38 and then follow it up with a 38 on a Tuesday, under the old system I would have one round entered with roughly a 4 differential. If I do that exact scenario now, I will have two entries both with roughly a 7 differential.  
 

Again, I’m not saying the new system is better or worse- my take is that recent handicap modifications outside of the new 9 hole modification seemed to make it easier to lower the handicap, this 9 hole modification unquestionably made it more difficult. 
 

 

Edited May 17, 2024 by jonflesh
Typo

[jonflesh]

5 minutes ago, jonflesh said:

 

 

 

 

Edited May 17, 2024 by jonflesh
Double post

[larrybud]

On 5/6/2024 at 12:32 PM, davep043 said:

The "expected differential" that is used as the second 9 is something near the average differential for all players with the same Handicap Index.  So if you shoot a really good 9, adding in an average 9 still makes a pretty good 18, but not as good as if you had a really good second 9.  Same if you play poorly for 9, the resulting 18 is still poor, just not as bad as.combining two bad 9s.  

 

The end effect of that is that players who play a fair number of 9 hole rounds will have their handicap increase, all other things being equal, more than players who don't play 9. You would have to shoot a REALLY low 9 hole score for it to end up being included in your best 8 of 20 differentials, because it's ALWAYS joined with an "average" differential, while a bad 9 holes generally would result in a worst 12 of 20 either by joining with another real 9 or with joining to the expected differential.

Edited May 17, 2024 by larrybud

[nsxguy]

Pollin', pollin', pollin', get those doggies pollin'

[iacas]

1 hour ago, jonflesh said:

I’m not saying the new system is “unfair” but it is unquestionably harder to lower the handicap. If a 7 is more representative of my actual skill than the 4 I had prior to the change then so be it.

 

The 7 is representative of your skill, and your index is representative of your potential. Your top 40%.

 

1 hour ago, jonflesh said:

But the new system effectively takes a really low round out of play for me.

 

No, it takes a low 9 out of play for you. Here's what I think a lot of people are not entirely understanding… your index is an 18-hole index. Trying to derive an 18-hole index from nine holes is always going to come with compromises. Previously, that was waiting (sometimes months or even longer) for another nine-hole score. Currently, it's nudging it (in BOTH directions; nobody's complaining about a front-nine 7 differential being combined with an average 5 differential for remaining holes) toward the average but posting it immediately for effect the next day.

 

Over the years I've seen many players talk or post about how "I shot 37 on the front, so I know I can shoot in the low 70s, but then shot 47 on the back! Holy cow!"

 

The simple truth is that it's easier to go low (or high) the fewer number of holes you've played. Any player can birdie a single hole: shooting 59, however, doesn't happen very often. Even bogey golfers can play two holes in two under. Fewer will play three holes in two under. Fewer still will play four holes in two under. And so on.

 

So while, yes, you can shoot below your index for nine holes, I feel like many people are assuming they won't go back to the average if they had played the back nine.

 

Let's assume a player has a 7 index but averages a 10 index over all 20 rounds. They shoot what would be a 3 differential on the front nine… there are three outcomes if they were to play the back nine:

• He shoots something like the front, a 3 differential for a 6 total.
• He shoots something like his average back nine, a 5 differential, for an 8 total.
• He shoots something bad on the back nine, a 7 differential, for a 10 total (or worse).

How likely do you think each of those is?

 

We know that the first one is pretty unlikely: shooting better than your actual index is about a 20% rate (4 out of 20). And that's without considering that a player might feel some stress or anxiety over playing so far better than their normal (or even their handicap index). How often does a player revert to the mean and play poorly on the back? I'll tell you this: it's much higher than 20%. The USGA is choosing the middle option: the player has an average back nine.

 

Imagine if the USGA's method was to figure out the odds (they could calculate them pretty well) and assign a back nine that aligns with the percentages. Sometimes you'd get your 6, sometimes you'd get a 12. Everyone would be confused about the rates at which the back nine scores were given out, and even though it might be by far the most accurate way to do this sort of thing, to convert a nine-hole score to an 18-hole differential, I am pretty confident almost nobody would like it or understand it (outside of the USGA) at all.

 

Too many people seem to be assuming their good play on the front nine would continue, when odds are… they might end up with a HIGHER differential if they continued to play than the one the USGA gives them. It might even be probable that they get a better differential with the USGA's method.

 

---------

 

At the end of the day, if you want your index to reflect how you actually play over 18 holes… the answer is simple: play 18 holes.

[jonflesh]

31 minutes ago, iacas said:

 

The 7 is representative of your skill, and your index is representative of your potential. Your top 40%.

 

 

No, it takes a low 9 out of play for you. Here's what I think a lot of people are not entirely understanding… your index is an 18-hole index. Trying to derive an 18-hole index from nine holes is always going to come with compromises. Previously, that was waiting (sometimes months or even longer) for another nine-hole score. Currently, it's nudging it (in BOTH directions; nobody's complaining about a front-nine 7 differential being combined with an average 5 differential for remaining holes) toward the average but posting it immediately for effect the next day.

 

Over the years I've seen many players talk or post about how "I shot 37 on the front, so I know I can shoot in the low 70s, but then shot 47 on the back! Holy cow!"

 

The simple truth is that it's easier to go low (or high) the fewer number of holes you've played. Any player can birdie a single hole: shooting 59, however, doesn't happen very often. Even bogey golfers can play two holes in two under. Fewer will play three holes in two under. Fewer still will play four holes in two under. And so on.

 

So while, yes, you can shoot below your index for nine holes, I feel like many people are assuming they won't go back to the average if they had played the back nine.

 

Let's assume a player has a 7 index but averages a 10 index over all 20 rounds. They shoot what would be a 3 differential on the front nine… there are three outcomes if they were to play the back nine:

• He shoots something like the front, a 3 differential for a 6 total.
• He shoots something like his average back nine, a 5 differential, for an 8 total.
• He shoots something bad on the back nine, a 7 differential, for a 10 total (or worse).

How likely do you think each of those is?

 

We know that the first one is pretty unlikely: shooting better than your actual index is about a 20% rate (4 out of 20). And that's without considering that a player might feel some stress or anxiety over playing so far better than their normal (or even their handicap index). How often does a player revert to the mean and play poorly on the back? I'll tell you this: it's much higher than 20%. The USGA is choosing the middle option: the player has an average back nine.

 

Imagine if the USGA's method was to figure out the odds (they could calculate them pretty well) and assign a back nine that aligns with the percentages. Sometimes you'd get your 6, sometimes you'd get a 12. Everyone would be confused about the rates at which the back nine scores were given out, and even though it might be by far the most accurate way to do this sort of thing, to convert a nine-hole score to an 18-hole differential, I am pretty confident almost nobody would like it or understand it (outside of the USGA) at all.

 

Too many people seem to be assuming their good play on the front nine would continue, when odds are… they might end up with a HIGHER differential if they continued to play than the one the USGA gives them. It might even be probable that they get a better differential with the USGA's method.

 

---------

 

At the end of the day, if you want your index to reflect how you actually play over 18 holes… the answer is simple: play 18 holes.

I don disagree with what you’re saying. But I think we are saying 2 different things.

 

You are arguing that the current format is a more accurate depiction of what an actual 18 hole round would be score wise and I am saying that the current format makes lowering your handicap more difficult if you primarily play 9 hole rounds. 
 

both of these can be true. As I said before, if the current format is a more accurate depiction of my actual handicap, I’m fine with it. 
 

With regard to my personal situation of primarily playing 9 holes, I’m hopeful that will soon be changing. One factor in is the club I am a member at is only 9 holes, and I’m moving out of the area in July and will join a new club which will be 18 holes. 

[larrybud]

37 minutes ago, iacas said:

 

Too many people seem to be assuming their good play on the front nine would continue, when odds are… they might end up with a HIGHER differential if they continued to play than the one the USGA gives them. It might even be probable that they get a better differential with the USGA's method.

That's not possible. Over time, they will always have a worse differential with the USGA derived method, because the 9 hole differential is being combined by the player's average differential, which is comprised of those 18 hole scores you're talking about.

Every time a score is posted, there's a 40% chance that you're rolling off a score which is part of the best 8 of your last 20. The combined differential of the Nine+average differential will, overall, be less likely to be part of the best 8 of 20, because it's being combined with an AVERAGE differential

[larrybud]

2 minutes ago, jonflesh said:

You are arguing that the current format is a more accurate depiction of what an actual 18 hole round would be score wise and I am saying that the current format makes lowering your handicap more difficult if you primarily play 9 hole rounds. 

In fact, your handicap will go UP over time if only play 9 hole rounds, even if you post the same set of scores over and over and over, because the 9 is always being combined with an AVERAGE differential, while your index is based on the average of the best 8 of the last 20.

Note, I'm working on some data sets to demonstrate all of this.

[iacas]

9 minutes ago, jonflesh said:

You are arguing that the current format is a more accurate depiction of what an actual 18 hole round would be score wise and I am saying that the current format makes lowering your handicap more difficult if you primarily play 9 hole rounds.

 

Yes, many things can be true:

• If you only play nine-hole rounds, then nobody can even really say what your actual index should be.
• If you play an occasional nine-hole round, then… this system is probably perfectly fine, and people saying that their 3.0 differential front-nine combining with a 5.0 differential back nine to give them an 8.0 differential off a 7.0 index are probably unjustified in their mild outrage. 😄 
• Handicaps are based off 18-hole scores, so no system of counting nine-hole rounds is going to be perfect for everyone all the time.
• People rely too much on made up examples and anecdata. The USGA has a ton of data on this.

 

 

7 minutes ago, larrybud said:

Over time, they will always have a worse differential with the USGA derived method, because the 9 hole differential is being combined by the player's average differential, which is comprised of those 18 hole scores you're talking about.

 

Of course.

 

But again… would you rather they create an algorithm that assigns a likelihood of shooting below, above, or at the average score for the back nine, like I wrote above? Nobody would understand that, or like it very much. Your front-nine 37 could be paired with a back-nine 47. Or your front-nine 47 could be paired with a back-nine 37.

 

No system is perfect, because the player should just play 18 holes… it's all an attempt to create a fair system. One that doesn't overly punish or reward people.

 

What's your proposed solution? It can't be "just double the nine-hole differential" because then you'd have guys complaining that their handicap went down unfairly and they're being robbed of strokes because of a "freak lucky nine holes they played a month ago" and stuff.

 

7 minutes ago, larrybud said:

Every time a score is posted, there's a 40% chance that you're rolling off a score which is part of the best 8 of your last 20. The combined differential of the Nine+average differential will, overall, be less likely to be part of the best 8 of 20, because it's being combined with an AVERAGE differential

 

And a 7.0 index might have a pair of 6.0s, four 7.0s, and two 8.0s counting. If our guy plays 9 holes at a 2.0 differential rate, and it's combined with a 5.0 for a 7.0, and that kicks an 8.0 out… his index goes down. (Not as much as if he shot 2.0 + 2.0, but still, it goes down).

 

Again, two main points:

• A handicap is representative of an 18-hole round. There can't be a perfect system for converting nine holes to 18. Not the previous system of combining nine-hole rounds sometimes played years apart, not the current system.
• If you're gonna complain about it (general "you" here), IMO you should present an alternative, and let others pick that apart.

Also, a bonus third point: people are often using small sample sizes or, even worse, just making up situations. Those can be illustrative, but we have no idea how often those things really even happen.

[jonflesh]

10 minutes ago, larrybud said:

In fact, your handicap will go UP over time if only play 9 hole rounds, even if you post the same set of scores over and over and over, because the 9 is always being combined with an AVERAGE differential, while your index is based on the average of the best 8 of the last 20.

Note, I'm working on some data sets to demonstrate all of this.

Thanks…Maybe I misunderstood the format used by the usga. 
 

Let’s say I’m a 7 index. I go out and play an 18 hole round and shoot a 95. If the majority of my rounds that follow the 95 are 9 hole rounds, is the usga formula factoring in the 95 to calculate how I would have finished on the unplayed 9 or are they only using my 8 lowest “counting rounds,” to calculate the unplayed 9?

 

if they are using scores that otherwise wouldn’t count toward my handicap (the 95), I might retract my statement about the new system only being harder but not being better or worse…it’s obviously harder and is worse in my opinion. 
 

If this is the case, players who only play 18 hole rounds can shoot an occasional round way over their handicap without penalty, while the 9 hole player is penalized for the occasional awful round. 

[larrybud]

12 minutes ago, jonflesh said:

Thanks…Maybe I misunderstood the format used by the usga. 
 

Let’s say I’m a 7 index. I go out and play an 18 hole round and shoot a 95. If the majority of my rounds that follow the 95 are 9 hole rounds, is the usga formula factoring in the 95 to calculate how I would have finished on the unplayed 9 or are they only using my 8 lowest “counting rounds,” to calculate the unplayed 9?

 

if they are using scores that otherwise wouldn’t count toward my handicap (the 95), I might retract my statement about the new system only being harder but not being better or worse…it’s obviously harder and is worse in my opinion. 
 

If this is the case, players who only play 18 hole rounds can shoot an occasional round way over their handicap without penalty, while the 9 hole player is penalized for the occasional awful round. 

They are using scores that otherwise wouldn't be in the best 8 of 20 to fill in the "expected differential". Your average differential is of course, higher than your handicap, since the handicap is based on the best 8 of 20 differentials.

 

[larrybud]

14 minutes ago, iacas said:

And a 7.0 index might have a pair of 6.0s, four 7.0s, and two 8.0s counting. If our guy plays 9 holes at a 2.0 differential rate, and it's combined with a 5.0 for a 7.0, and that kicks an 8.0 out… his index goes down. (Not as much as if he shot 2.0 + 2.0, but still, it goes down).

 

Again, two main points:

• A handicap is representative of an 18-hole round. There can't be a perfect system for converting nine holes to 18. Not the previous system of combining nine-hole rounds sometimes played years apart, not the current system.
• If you're gonna complain about it (general "you" here), IMO you should present an alternative, and let others pick that apart.

Also, a bonus third point: people are often using small sample sizes or, even worse, just making up situations. Those can be illustrative, but we have no idea how often those things really even happen.

 

Yes, a single 9 hole score *could* make the player's index to go down (it would have to be quite a good differential relative to the player's index), but over time, 9 hole scores will make the player's index go up. I take your third bonus point seriously, which is why I'm not giving a single differential example.

Also, based on data sets that I have, you're vastly underestimating what a 7 index's average differential is. It's certainly higher than 10, more like 13-14 for the average player.

[iacas]

4 minutes ago, larrybud said:

Yes, a single 9 hole score *could* make the player's index to go down (it would have to be quite a good differential relative to the player's index), but over time, 9 hole scores will make the player's index go up. I take your third bonus point seriously, which is why I'm not giving a single differential example.

Also, based on data sets that I have, you're vastly underestimating what a 7 index's average differential is. It's certainly higher than 10, more like 13-14 for the average player.

 

I was one of the first people to make that point weeks ago, so yes, I know that.

 

If you primarily play nine-hole rounds, you can't say for certain what your 18-hole index should be. And nobody's putting forth any propositions; they're just whining about the format the USGA put in place (to replace a previous system, and they're not really one to change just for the sake of change).

 

[larrybud]

15 minutes ago, iacas said:

 

I was one of the first people to make that point weeks ago, so yes, I know that.

 

If you primarily play nine-hole rounds, you can't say for certain what your 18-hole index should be. And nobody's putting forth any propositions; they're just whining about the format the USGA put in place (to replace a previous system, and they're not really one to change just for the sake of change).

 

My proposition is simple: Revert the 9 hole combination, and also include a Competition Index in a player's calculation, which only includes competition rounds.

[davep043]

36 minutes ago, jonflesh said:

is the usga formula factoring in the 95

No, they are using scores from every single player with the same index as you.  This was made clear at a Handicap Workshop I attended this Spring.

 

17 minutes ago, larrybud said:

Also, based on data sets that I have, you're vastly underestimating what a 7 index's average differential is. It's certainly higher than 10, more like 13-14 for the average player.

I think you need to find more data.  I'll give you two data points.  My index is 7.0, significantly impacted by a single low round.  My average diff is 10.3, significantly impacted by some really high scores.  So that difference is 3.3.  Another data point, about a year ago my index was 6.3, my average diff was 9.4, a variation of 3.1.  So perhaps we're giving the WHS a bad rap, perhaps they're using something a bit lower than the "average" differential for that second 9.  In each case, if my differential for 9 was 2 strokes better than my average, and combined per the current system, it would be in the best 8 scores.  3 strokes lower gets me below my index.

[Newby]

21 minutes ago, davep043 said:

No, they are using scores from every single player with the same index as you.  This was made clear at a Handicap Workshop I attended this Spring.

 

I think you need to find more data.  I'll give you two data points.  My index is 7.0, significantly impacted by a single low round.  My average diff is 10.3, significantly impacted by some really high scores.  So that difference is 3.3.  Another data point, about a year ago my index was 6.3, my average diff was 9.4, a variation of 3.1.  So perhaps we're giving the WHS a bad rap, perhaps they're using something a bit lower than the "average" differential for that second 9.  In each case, if my differential for 9 was 2 strokes better than my average, and combined per the current system, it would be in the best 8 scores.  3 strokes lower gets me below my index.

Two points.

Your first paragraph has been confirmed by England Golf.

 

What do you mean by "My average differential"? Given that your Index is the average of your best 8 from the last 20, how many scores are used for your 'average' and over what time frame?

Edited May 17, 2024 by Newby

[jonflesh]

13 minutes ago, davep043 said:

No, they are using scores from every single player with the same index as you.  This was made clear at a Handicap Workshop I attended this Spring

Thanks  This is helpful.

 

It still seems off to me that as a 7 handicap, who used to be a 4 as of 12/31/23 in the old system, and given my recent 38 on a par 36, 35.5/136 course being entered as a 7.1, to currently get a score of a 4 differential entered into my scores I would have to shoot a 35(-1).

 

There is pretty clearly no path back to the 4 range playing 9 holes for me unless I drastically improve my game given I’ve broken par on 9 holes maybe 1-2x in my life. 

[larrybud]

6 minutes ago, davep043 said:

No, they are using scores from every single player with the same index as you.  This was made clear at a Handicap Workshop I attended this Spring.

 

I think you need to find more data.  I'll give you two data points.  My index is 7.0, significantly impacted by a single low round.  My average diff is 10.3, significantly impacted by some really high scores.  So that difference is 3.3.  Another data point, about a year ago my index was 6.3, my average diff was 9.4, a variation of 3.1.  So perhaps we're giving the WHS a bad rap, perhaps they're using something a bit lower than the "average" differential for that second 9.  In each case, if my differential for 9 was 2 strokes better than my average, and combined per the current system, it would be in the best 8 scores.  3 strokes lower gets me below my index.

 

I mean, I have a couple million scores... Also, from my dataset for 9 holes, they are adding something slightly HIGHER than my average differential of the last 20, but your first sentence probably explains that.

But take your example, shooting 3 strokes lower than your average differential for 9 holes would be a 1.65 differential for 9 (6.3 - 3 =3.3, divided by 2 = 1.65 differential).  Equivalent of a 3.3 differential for 18 holes.

 

Now, I don't think the USGA ever published a new "exceptional score" table, but with the old table, a 6 index shooting 3.3 strokes under their index is 51:1. So yes, in the 51 to 1 chance you shoot that, your index will go down (note 2 strokes better is 22:1) when combined with what the usga calls the "scaled up differential" (at least, that's what they call it in the raw data the GHIN site returns).

 

Your index, however, over time, will go up posting primarily 9 hole scores, even with the same set of 9 hole scores posted over and over, since it's being combined with an "average" differential. 

[larrybud]

I think everybody should keep a separate spreadsheet of their handicap with the old combining method and see the difference as they post 9 hole scores this year. I'm currently +0.2 using the new method over the old method, with just 8 9-hole scores posted in 6 weeks, and 9 18-hole rounds. So about a 50% split.

[DaveLeeNC]

I don't know what improvement that the USGA saw with this new procedure vs. the old one. But I will say (now that half my rounds are 9 hole rounds) this is a profoundly unsatisfying way to calculate a handicap (just my view). I used to use my index as kind of a global measure of how I am playing. Now that half my posted scores are some average of 'how I actually played' (9 hole differential) and some other number that is correlated to (but not strictly equal to) how I played over the last 20 posted rounds, I am keeping a separate handicap that I use as my personal measure of how I am playing. 

 

dave

Edited May 17, 2024 by DaveLeeNC