grinter001
5 minutes
I am sure you know that Golf Handicaps are calculated for 18 hole rounds. But did you know that if you only play 9 hole rounds you would have a Handicap Index called N?
You will see in our Trends section that there are a set of "9 Hole Rounds" graphs. In there you will be able to see your Handicap Index N which is calculated using your 9 hole rounds. (it won't show if you don't have any 9 hole rounds)
To calculate this handicap you simply use the course rating of the 9 holes you played and use the same formula you use for 18 hole Handicaps. You will see that this handicap ranges from 0-18 instead of 0-36 like the regular Handicap Index.
NOTE that 9 hole rounds are not utilized for the regular Handicap Index calculation.
Well, the USGA doesn't really explain the reasoning behind having two different handicaps but based on all my readings and interpretations of the USGA thinking, I will give you my best guess. (so please interpret this post as my opinion and not the USGA's)
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"Playing 9 hole rounds requires different level of concentration than 18 hole rounds. Keeping the focus for 18 holes (~4.5 hours) is much more difficult. So it wouldn't really be fair to multiply by 2 the score and then get the equivalent 18 hole round score."
But I figured you wouldn't believe it so I ran a couple of analyses, here they are!
What would be my handicap if I calculated front and back nine separately?
We looked at 5 different golfers, and while there is only significant difference in 2 of them, it is; in my opinion, enough . See the graph below comparing the handicaps of 18 hole rounds versus the handicap calculating every 9 holes (multiplying by 2)
Look at golfer 1 and golfer 5. There are ~4 points difference between the regular handicap and the equivalent handicap we calculated using their 9 hole rounds. And out of the 5 there is only one of them that have less than 1 point difference.
What is the average difference between the front and back 9 per round?
We looked at the front 9 and back 9 of the same 5 golfers. We found that the difference between the two average 4.2 strokes. That means that on average, those golfers had a 4 strokes difference between the front 9 and the back nine. So, if one of this 5 golfers shoot 44 on the front 9, he was expected to shoot a 40 or a 48 on the back 9. That's a lot of strokes since 4.2 would mean a 8.4 difference on a 18 hole round.
I know that this is not enough statistical proof and that we would have too look at a larger sampler. But I do believe that it is a lot easier for the regular golfer to shoot a 41 on 9 holes than it is to shoot an 82 on 18 holes. So you be the judge, but I think the USGA is right in separating the two and having a Handicap Index (18 Holes) and a Handicap Index N (9 holes).
What do you think?
Enjoy your golf!
