Score Differential question on EG app

[evemccc]

I played yesterday evening and shot a certain score…an acquaintance of mine, who’s got a lower HI by several strokes played an hour earlier off the same tees

I checked the EG app today to see what he shot - yet although I (miraculously) was a couple of strokes lower, his Score Diff for the round is notably lower (by 0.8) than what my Score Diff was for the round…

Why is that, and what I am seemingly not understanding..?

 

[doublebogey7]

I played yesterday evening and shot a certain score…an acquaintance of mine, who’s got a lower HI by several strokes played an hour earlier off the same tees

I checked the EG app today to see what he shot - yet although I (miraculously) was a couple of strokes lower, his Score Diff for the round is notably lower (by 0.8) than what my Score Diff was for the round…

Why is that, and what I am seemingly not understanding..?

Did he have hole/s where he shot more than net double bogey??

 

[rulefan]

We need the numbers for both.
HI, Gross Score, CR, Slope

 

[evemccc]

Here’s the data:
13.5
37
33.2
119


And

5.6
40
33.2
119

I am not too concerned as he’s a very honest person - as I am - I guess I just thought I understood Score Diff…and maybe I don’t ??

 

[evemccc]

Did he have hole/s where he shot more than net double bogey??

no I don’t think so

 

[RichA]

If one of you has had an exceptional round recently (good or bad) it will manipulate certain score diffs to make the appropriate adjustment.

 

[rulefan]

Here’s the data:
13.5
37
33.2
119


And

5.6
40
33.2
119

I am not too concerned as he’s a very honest person - as I am - I guess I just thought I understood Score Diff…and maybe I don’t ??

Was it a 9 hole round on a 9 hole course? If so we need the 9 hole par.

 

[RichA]

If one of you has had an exceptional round recently (good or bad) it will manipulate certain score diffs to make the appropriate adjustment.

Just been doing some maths and this might be BS.
Although when I had a wonder round back in the summer, all my score diff 17 in my last 20 rounds suddenly became score diff 16.

 

[evemccc]

Was it a 9 hole round on a 9 hole course? If so we need the 9 hole par.

Par 33

Yes - 9 hole round on 9 hole course — both ‘Front 9’ on app

 

[evemccc]

If one of you has had an exceptional round recently (good or bad) it will manipulate certain score diffs to make the appropriate adjustment.

It was an unusually good round for me
And definitely it was worse than usual for him

 

[wjemather]

For handicapping, a 9-hole score is 'scaled up' to an 18-hole score by adding a 17 point (Stableford) equivalent adjusted gross 9 hole score over the same 9 holes that were actually played. This second 9 score is therefore dependent on handicap, so will have been a few strokes less for your friend than for you. The result of all this is that his overall differential ends up being slightly lower than yours.

Happy to do/show the arithmetic for this case if you want!

 

[rulefan]

5.1b For a 9-hole Score
A 9-hole score is scaled up to an equivalent 18-hole Score Differential for immediate use in the scoring record.
* A 9-hole score is scaled up to an equivalent 18-hole Score Differential by adding net pars for the remaining holes plus one additional stroke (which is applied to the first hole not played), or 17 points in Stableford format (see Diagram 5.1b/1).
* The second 9 holes used for scaling up is always the same 9 holes that have been played.

A 9-hole score is scaled up to an equivalent 18-hole Score Differential as follows and rounded to the nearest tenth, with .5 rounded upwards:

Score Differential = (113 ÷ Slope Rating) x (adjusted gross score – Course Rating – (0.5 x PCC adjustment))
Where:
*l Slope Rating equals the 9-hole Slope Rating of the 9 holes played.
* Adjusted gross score equals the adjusted gross score for the 9 holes played, plus net pars for the second nine holes plus one additional stroke. It is calculated using the 18-hole Course Handicap, based on the 9 holes played.
* Course Rating equals the Course Rating of the 9 holes played, doubled.
* 50% of the playing conditions calculation (PCC) for the day is applied.

Notes:
1. For the calculation of an 18-hole Course Handicap based on the 9 holes played, see Rule 6.1a.
2. An 18-hole PCC adjustment ranges from -1.0 to +3.0 (see Rule 5.6).


Edit: I started to do this last night but thought I'd leave it to this am but see wje is a night hawk.

 

[evemccc]

5.1b For a 9-hole Score
A 9-hole score is scaled up to an equivalent 18-hole Score Differential for immediate use in the scoring record.
* A 9-hole score is scaled up to an equivalent 18-hole Score Differential by adding net pars for the remaining holes plus one additional stroke (which is applied to the first hole not played), or 17 points in Stableford format (see Diagram 5.1b/1).
* The second 9 holes used for scaling up is always the same 9 holes that have been played.

A 9-hole score is scaled up to an equivalent 18-hole Score Differential as follows and rounded to the nearest tenth, with .5 rounded upwards:

Score Differential = (113 ÷ Slope Rating) x (adjusted gross score – Course Rating – (0.5 x PCC adjustment))
Where:
*l Slope Rating equals the 9-hole Slope Rating of the 9 holes played.
* Adjusted gross score equals the adjusted gross score for the 9 holes played, plus net pars for the second nine holes plus one additional stroke. It is calculated using the 18-hole Course Handicap, based on the 9 holes played.
* Course Rating equals the Course Rating of the 9 holes played, doubled.
* 50% of the playing conditions calculation (PCC) for the day is applied.

Notes:
1. For the calculation of an 18-hole Course Handicap based on the 9 holes played, see Rule 6.1a.
2. An 18-hole PCC adjustment ranges from -1.0 to +3.0 (see Rule 5.6).


Edit: I started to do this last night but thought I'd leave it to this am but see wje is a night hawk.

Thanks to you and @wjemather for detailed explanation