An "Annual" Handicap Index

[bkuehn1952]

Our handicap indexes are in constant motion.  Every 1st and 15th of the month we get a new index value and our trend index is pretty much constantly in motion.  It makes personal comparisons a bit hard.  If I spent most of the summer bouncing between 8.2 and 7.8, was 2015 a better year handicap-wise than last year when for one 15 day period my index dropped to 6.9 while the rest of the time it was between 8.4 and 8.9?

It might be interesting to compute one's "Annual Handicap Index".  Take every differential for 2015, toss out the 50% highest, average the balance and multiply by .96.  If your "Annual Handicap Index" for 2015 is 8.2 and 2014 was 7.9, you know you have regressed and if the numbers are reversed, you know you are improving.

I am not a math whizz but I don't think one can just average all the bimonthly indexes.  For one thing, some scores from the prior year affect the current year's indexes early in the year.  For me, I have tracked my gross scores and calculate an average each year.  That method is inaccurate because of possible differences in the quality/difficulty of courses played in a given year and there is no "ESC".  I might give this a try as the state golf association has all my scoring records and differentials going back to 2007.

[sjduffers]

I wouldn't worry about a 0.3 difference in either direction, unless I was below 2 or 3. It's just noise. IMHO, unless you can spot more than a 10% change (i.e. one full stroke for a 10 handicapper), don't sweat it. It could be weather related, equipment related, too much play, not enough play, luck, you name it...  Any significant effort you would make to work on and improve your game is likely to have a benefit greater than 10% if it's working: otherwise, why bother?

[No Mulligans]

If I was trying to measure year over year performance I wouldn't use an HI, I'd just average all my scores.

For me I'm not just interested in my top 50% differentials, I'm interested in all my scores as a measurement of year to year change.  I'm hoping my worse scores are also getting better and my variance from mean is getting smaller (less blowups).  All of that would be an indication of improvement.

Edited October 16, 2015 by No Mulligans

[bkuehn1952]

If I was trying to measure year over year performance I wouldn't use an HI, I'd just average all my scores.

For me I'm not just interested in my top 50% differentials, I'm interested in all my scores as a measurement of year to year change.  I'm hoping my worse scores are also getting better and my variance from mean is getting smaller (less blowups).  All of that would be an indication of improvement.

Fair point.  If one always played the same course & tee, an average of the scores could be a good measure of year over year change.  If you are like me, however, typically 25-30 different courses are played over a season and often different tees for the same course.  While the average rating and slope might work out to be identical every year, my guess is the average difficulty varies, perhaps by a significant amount.  So the average of my scores from 2014 doesn't necessarily compared well with 2015 when the line up of courses played has changed substantially.  In my case, comparing the average of all differentials for a year probably is more accurate.

[saevel25]

Since handicap is suppose to be such that you only beat your handicap 20% of the time no matter what the skill level. I would take the top 20% of your differentials for the whole year. 

[bkuehn1952]

Just fiddling with the numbers for 2014 and 2015 year to date, I was a bit surprised that the average course rating and slope was virtually the same (2014: 69.9 / 123 versus 2015: 70.0/124).  So maybe just comparing average score for the year, in my case, is reasonably valid.

As to my "Annual" handicap index, 2014 was 8.9 and 2015 (year to date) is 8.1, which largely mirrors my impression of my play last year and this year.

 

Using just the lowest 20% of differentials the "Annual" numbers are 7.6 versus 6.5 which is consistent with the other numbers.

[sjduffers]

As to my "Annual" handicap index, 2014 was 8.9 and 2015 (year to date) is 8.1, which largely mirrors my impression of my play last year and this year.

That is nearly a 10% improvement, something both noticeable and to be proud of. Well done! 

[No Mulligans]

Fair point.  If one always played the same course & tee, an average of the scores could be a good measure of year over year change.  If you are like me, however, typically 25-30 different courses are played over a season and often different tees for the same course.  While the average rating and slope might work out to be identical every year, my guess is the average difficulty varies, perhaps by a significant amount.  So the average of my scores from 2014 doesn't necessarily compared well with 2015 when the line up of courses played has changed substantially.  In my case, comparing the average of all differentials for a year probably is more accurate.

Yes you are right.  I meant an average of all your differentials (but old age set in and I typed scores instead).

[DrvFrShow]

But then for me, my home course with my club plays 69.1/112 on 5200 yds. Last year I played 25 rounds there. This year I played 6. The rest of my rounds were on courses no shorter than 5500 yds with ratings of 71.8/124 up to 74/121 and 5800 yds. I score better on the longer courses. Does this mean I play better golf? No. Did it lower my handicap? Yes.