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The Golf Handicap – Threat or Menace?
How are handicaps calculated? I’ve read (and written) a number of explanations and they seem to fall
into two main groups 1) detailed, complete, sleep inducing and for the most part longer than a Tolstoy
novel. And 2) short concise and so devoid of detail that they don’t actually answer the question.
Since I am (among other things) the handicap committee for our league I am more familiar with the ins
and outs of handicapping than any rational man should be. So I thought I'd try to explain just how we do
things. For the most part, we follow the USGA handicapping system but with a few modifications to
better suit our league. If you really want to know all about the USGA handicapping system, you can read
about it here:
http://www.usga.org/Rule-Books/Handicap-System-Manual/Handicap-Manual/
For the rest of us, I’ll give you the short version and then expand on the various steps if you are still
interested. Here goes
Handicapping – the short version
We begin with your hole-by-hole scores from the weekly scorecards. Before these scores can be used for
handicap purposes they are subject to several adjustments. Chief amongst these is the application of
“equitable stroke control” (ESC). Basically, if you do VERY badly on a particular hole, not all of the
strokes will count toward your handicap calculations. If you look at the results page on our website you
will see gross scores (Gr) adjusted scores (Adj) and net scores (after handicap).
Next, your adjusted score needs to be normalized in some way to allow for the varying difficulty of
different golf courses. The USGA assigns every golf course 2 numbers that measure difficulty: The rating
and the slope. These appear on the score card usually something like “70.7/127”. This means a course
rating of 70.7 and a slope of 129. The meaning of these numbers will need some explanation (see
below) but for now, just know that that they measure difficulty and that the higher the number the
harder the course.
So, based on your adjusted score, along with the course rating and slope we calculate what is known as a
“differential”. Simply put this is a single number that sums up how good/bad your score for the round
really was. It normalizes your score for par, for the difficulty of the course and makes allowances for any
abnormally bad holes, ESC even accounts for your existing handicap (i.e. how bad is an abnormally bad
hole for someone of YOUR ability). The formula used to calculate differentials is:
Differential = ((adjusted score – rating) X (113/slope)).
Once you play a few rounds we can use you various differentials to calculate a handicap. The USGA
calculates your “handicap index” by averaging the lowest 10 of your 20 most recent 18 hole differentials,
and then multiplying that average by .96 (yeah I know, I’ll explain later). For league purposes, we
average the lowest 5 of your 10 most recent 9 hole differentials and, again, multiply by .96. That’s your
handicap. Please note, the handicap index is portable. The whole rating/slope thing means that the
handicap index is independent of what course/set of tees you play from.
Now, when you play a specific course, you need to adjust this “portable handicap” based on the difficulty
of that course. For any given golf course, a course handicap can be calculated using the course slope.
Once again, if you look at the “latest results” page you’ll see your handicap index, as well as your course
handicap for both the north and the south courses. The formula is:
Course handicap = handicap index X (slope / 113)
So there you go, that’s the short version. Now let me offer a little more detail into some of these steps
Equitable Stroke Control
For scoring purposes, the Rules of Golf do not limit the number of strokes a player may take on any one
hole. If it requires seventeen strokes to hole out (including penalty strokes) then your score for that hole
is "17". However, there is a maximum number of strokes that will be counted for handicapping
purposes. This maximum score varies according to your current handicap. It could be as low as double
bogey or as high as 10 (regardless of par for the hole). So if your score for a given round contains any
holes that are especially bad, they will be adjusted downward. The mechanism used to do all this is
called “equitable stroke control” or “ESC”. The equitable stroke control table is as follows. Note the left
hand column is course handicap not handicap index (see discussion above). Further note the handicaps
listed are for 18 holes. (so...for 9 holes divide by 2)
The reasons for using a scheme like ESC are twofold. First, the whole idea of establishing a handicap is to
predict what a given golfers “typical” round should look like. As we all know, even a good golfer will
occasionally have a truly awful hole. These Hindenburg class failures are in no way “typical” and giving
them full weight in the handicapping calculation will unduly influence things. Secondly….no one likes a
sandbagger. By using ESC, the USGA discourages “handicap management” (i.e. intentionally 6 putting
after you know you’ve lost the hole, just to inflate your score and keep you handicap higher for next
week). If you want to run up your score on a given hole, I can’t stop you. BUT I won’t be counting all of
those strokes toward your handicap either.
Please note: Although there is no limit to the number of strokes you may make on a hole, there is a
practical limit to the number of strokes you should attempt on a hole. It is generally considered bad
form to take more than 10 strokes on a hole because it holds up the groups behind you and will cause
the marshal to visit you with a warning to speed up your play. Not to mention some ugly confrontations
in the parking lot when the group behind you finishes play. If you have not holed out after 10 strokes,
just pick up the ball and mark the scorecard with an “X”.
Today’s fun fact: The handicapping scheme used by the British uses a different (and in some ways
superior) scheme to limit the handicap impact of truly awful holes. Under their system, the maximum
score (again for handicap purposes) is a NET double bogey. The big advantage is that the max score for a
hole varies with par for that hole (lower for par 3’s, higher for par 5’s)
Rating and Slope
The USGA has a theoretical model of what a scratch golfer (zero handicap) should be able to do. He
should hit his drive so far with so much accuracy etc. They use this model to calculate how a 0
handicapper should be able to get around the course from a given set of tees. For example, they may
say that their imaginary scratch golfer should hit his tee shot so many yards with a certain level of
accuracy. So his average drive should end up about yonder with a certain percentage in the left rough,
right rough, fairway, bunker etc. Based on that, his average second shot would be so many yards with a
certain percentage coming from the fairway/rough/bunker. Based on the distance and the size of the
green, they calculate how many approach shots would land on the green / in the rough/ in a bunker and
so on and so on until they come up with what they consider the typical score for a zero handicapper
should be. This theoretical number is calculated to the 1/10 of a stroke and becomes the “USGA rating”
for that course. Please note, the course rating may be greater or less than par.
In addition, the USGA has a model of the theoretical bogey golfer (18 handicapper). Using the same
methodology, they calculate what an 18 handicapper should be able to do on the same course. Note,
the 18 handicappers score could differ from the 0 handicappers score by more or less than 18 strokes.
“Why” you ask? Consider a hole with a 200 yard forced carry over water. This is a big problem for the
bogey golfer but merely “scenic” for the scratch golfer. On this hole the bogey golfers’ average score is
likely to be more than one stroke greater than the scratch golfer. On the other hand consider a hole with
a forced lay-up off the tee (10 North). The scratch golfers additional length off the tee is wasted
(everybody has to lay up short of the water) and since the fairway is so wide, added accuracy is of little
value (on 10 North, you can spray things pretty badly and still find the fairway SOMEWHERE). On this
hole the bogey golfers’ average score is likely to be less than one stroke worse than the scratch golfer.
Based on the difference between the two theoretical scores, the USGA calculates a number called “the
slope” which is normalized around an arbitrary constant (113). Note, some sources claim that 113 is the
average slope for courses in the US. It is not. It was chosen based on what the creators of the handicap
scheme THOUGHT the average slope might be (turns out they were wrong). In the end it doesn’t matter,
it’s just a number. In any event, the higher the slope, the more difficult the course will be for high
handicappers. So if a high handicapper and a low handicapper play together on a low slope course their
scores should be (relatively) close to one another. As the slope increases, so should the spread between
the two golfer’s scores.
Please note that rating and slope are calculated separately for each set of tees and that there is a
separate theoretical model for male and female golfers. If you go to the USGA database, they will list
rating and slope for both male and female players for most sets of tees (so for example there will be
separate male and female numbers for the white tees). On the scorecard, most courses list only the
male numbers for the blues and whites and only the female numbers for the reds, but, for example, if a
male player wants to play from the reds (senior), those numbers are available and relatively easy to find.
Taken together the rating and the slope can be used to provide an “apples to apples” comparison of
scores from different courses. As I said earlier, use of these numbers, along with adjusted score (i.e.
after application of equitable stroke control) yields a number called a “differential”. Differentials are
typically calculated to 1/10th point and sum up numerically how good or bad a round you just had. It
accounts for the course played, the tee boxes used, the expected level of proficiency based on your past
play (i.e. handicap). One simple number sums it all up. Genius!
Another fun fact about the British system. They base their scheme on what they call the “Standard
Scratch Score” or SSS. This purports to measure exactly the same thing as the USGA rating but was
traditionally calculated using a different methodology. Further fun fact, the national golf unions of
several nations (notably Ireland and Wales) have adopted the USGA course rating methodology. So, in
those countries, they still use the British handicapping scheme but they use the USGA course rating
methodology to calculate SSS, however, they don’t use slope. (Got it?).
Handicap Index
The USGA calculates your “handicap index” by averaging the lowest 10 of your 20 most recent 18 hole
differentials, and then multiplying that average by .96. We use the lowest 5 of your 10 most recent 9
hole differentials (it makes handicaps move up and down more quickly and that suits our league). The
.96 multiplier is called the “bonus for excellence” (great name no?). The idea is that if the handicapping
scheme were perfectly fair then a 30 handicapper could beat a pro ½ the time (on handicap). In practice,
the better golfer should be rewarded (a little) for being a better golfer. By multiplying by .96, the better
golfer is given an advantage equal to 4% of the difference in the two golfer’s handicaps (that 4% is his
bonus for excellence).
NOTE: As I said earlier, no one likes a sandbagger. Since your handicap is based on only the best 5 of
your 10 most recent rounds, it discourages the aforementioned handicap management. If you were to
intentionally run up your score on a given round, then that round would NOT be one of you best 5 and
would NOT be considered when calculating you handicap (so knock it off).
BIG HONKING NOTE: Many people think that that the handicap scheme should ensure that their average
net score should be right at par (36 for 9). This is NOT the case. Please note that the handicap
calculation only considers ½ of your scores (the better half). Also, the bonus for excellence means that
you don’t get 100% of the average. Finally, remember that the expected average score of a zero
handicapper is NOT par (it’s the course rating). If you enjoy math puzzles, it is possible to calculate the
expected average score for your “good” rounds (better half of rounds played) but…what’s the point?
Course Handicap
Based on your handicap index and the slope of a given course it is possible to calculate a course
handicap (see the formula above....I'll wait... Oh all right, I’ll repeat myself and put the formula here as
well)
Course handicap = handicap index X (slope / 113)
You will note that this formula uses the “slope” but NOT “course rating”. Let me explain. Remember,
from our discussion of rating and slope, the rating seeks to measure what a zero handicapper might
shoot on a given course and the slope seeks to measure how much that score would increase as
handicap increases. If I were trying to predict your score, based on your handicap, I would need to factor
in course rating. However, I’m really only trying to predict the DIFFERENCE between your score and your
opponents. If two golfers, of differing abilities were to play on different courses, BOTH of their scores
would go up or down based on the course rating of those courses. The DIFFERENCE between their
scores would go up or down based on the slope. So when we’re trying to figure out who’s giving who
how many strokes the course rating gets factored out because it’s the same for both golfers.
Keen eyed mathematicians will have noticed the flaw in my last statement. Note that I said “the course
rating is the same for both golfers”. Since rating and slope is specific to a particular set of tees and is
calculated separately for male and female golfers this is not always the case. If you are playing against a
member of the opposite sex or if one member of your group decides to play from a different set of tees,
there are special adjustments that need to get made when figuring who is giving who strokes (i.e. you
need to factor in the course rating after all).
How do our league handicaps differs from the USGA system?
As I said earlier, we follow the spirit of the USGA scheme with only a few modifications.
•
Strictly speaking, we do not follow the USGA rules of golf. In particular the “Everything is a
lateral hazard” rule can affect your score. Consider what happens if you hit your tee shot out of bounds.
In our league you take a drop where the ball went OB and play on (lying 2). The USGA would have you
take a penalty stroke and hit a second tee shot (after which you’d be lying 3). For our purposes, this is a
good rule in that it helps speed up play. However, if you were to take advantage of this rule, your round
would not have been played according to the rules of golf and the resulting score should not be used to
calculate a USGA handicap. (but if you were to use the score I wouldn't tell...happens all the time)
•
We calculate “9 hole differentials” rather than “18 hole differentials”. The USGA really, really,
really wants to deal with 18-hole scores. There are a set of rules for combining two 9-hole scores to
make one 18-hole score. Of course, since the USGA thoughtfully publishes separate rating and slope info
for the front and back 9 of most courses we can and do calculate 9-hole differentials and then use them
to generate 9-hole handicaps. It just suits us better that way.
•
We get by with less data. The USGA won’t issue a handicap without at least 5 differentials to
work with and will use data from your last 20 18-hole rounds (360 holes of golf) in the calculation. We’re
not so fussy. We will concoct a handicap based on a single 9-hole score if need be and will only look at
your last 10 9-hole rounds (90 holes of golf) in our calculations.
•
BIGGY: The USGA specifies a maximum for handicap index. We used to adhere to this limit but
we found that it was unfair to a few of our members (essentially their handicap was capped at too low a
number and they couldn't compete fairly). We chose to eliminate this maximum and let their handicaps
rise as high as necessary. However, we also determined that really high handicapper tended to have
more than their share of terrible holes (10's and X's) and that these holes unduly influenced their
handicaps. So we also eliminated the last line of the ESC table as well (for our handicapping purposes,
you cannot score higher than a 9 no matter what your handicap). You will note that this change ONLY
impacts golfers with very high handicaps (i.e. if your course handicap is under 20 per side ESC was
already limiting your hole scores to 9 or less. So for most golfers....no change). Our experience with this
rule change has been VERY positive.
So what does this mean to you? Not all that much really. If you want to enter any serious tournaments
you will not be able to use our league handicaps. You will need to establish a UGA handicap typically
through the GHIN system (ask me, I’ll explain). However, since our handicap calculations are at least
“USGA-like” our league handicaps should be pretty close to their USGA equivalents. You should be able
to use our league handicaps in less formal competitions (just remember to double our 9-hole handicaps
to get an 18-hole handicap).
If you have any questions about the handicapping scheme, buy me a beer and I will happily bore you to
tears droning on about the whole she-bang. Otherwise.....just trust me. Your handicap numbers will
appear of the league website every week. One final note: If you really, really, really want to nitpick over
1/10 strokes on your handicap index...you may find yourself the brand new chairman of the handicap
committee. You have been warned.