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Okay so I’m reading the latest Golf Digest and I ran into a Q&A about handicaps. I recently tried to explain to a friend that handicaps aren’t what you should be expected to shoot above par.  This sums it up nicely:

Q: How often should you beat your handicap?

A: Not often. In fact, you should average about three shots higher than your handicap.

For example, if you have a course handicap of 16, and the Course Rating is 71.2, you should average 90, not 87. The USGA Handicap System is based on 96 percent of the best 10 differentials (corrected for Course and Slope ratings) of your last 20 rounds. More than half of your scores should be within three strokes of three over your handicap (87 to 93 in this example). Most golfers beat their handicap (86 or better in this example) only 20 percent of the time and beat it by three strokes one out of every 20 rounds.

For a person with a course handicap of 16 to break 80 (beat his handicap by eight strokes), the odds are 1,138 to 1. To do it twice, it would take the average golfer more than 700 years. In other words, it ain’t happening.

Source: Golf Digest, May 2008

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Okay so check this out. The USGA has a bunch of numbers that represent how good a player is, how tough a course is, etc. At first glance they seem like they might make sense. The math behind them boggles the mind.

USGA Course Rating. Through some documented procedures, a USGA team must come and evaluate the course. The number this represents is what they believe a scratch golfer should shoot on the course, when the course is playing in average conditions. Lots of variables, some black box math, and they’ve got a number that has one decimal place.

Bogey Rating. At the same time of the USGA Course Rating, the team also determines what a bogey golfer should shoot. You with me? They’re trying to determine what somebody who makes bogey every hole on an average course of average condition playing in average weather would shoot at the course in question when playing in its average conditions. This number is certainly not scratch plus 18 strokes.

Handicap Index. This is probably the number you’re familiar with. Us duffers will be well into the double digits here - I’m a 19 handicap or so. Now you may think this is just the average over par you are after 18 holes. Thinking it is that easy makes you look like a schmuck. Here’s how the USGA defines a Handicap Index:

A “Handicap Index” is the USGA’s service mark used to indicate a measurement of a player’s potential ability on a course of standard playing difficulty. It is expressed as a number taken to one decimal place (e.g. 10.4) and is used for conversion to a Course Handicap.

Okay, so let’s see how we actually figure it out. First, you must be able to calculate Handicap Differentials. To do that, you’ll need your adjusted gross score, the USGA Course Rating, Slope Rating, and the magic number 113 (I’m not kidding). Here’s how the USGA describes this process:

To determine the Handicap Differential, subtract the USGA Course Rating from the adjusted gross score; multiply the difference by 113; then divide the resulting number by the Slope Rating. Round the final number to the nearest tenth.

Handicap Differential = (Adjusted Gross Score - USGA Course Rating) x 113 / Slope Rating

Now, depending on how many rounds you’ve played and you’ve calculated the Handicap Differentials for, you’re going to take about half of them. You take the lowest 10 of your last 20 or if you only have say 16, you’ll use your lowest 6 for some reason (there is a sliding scale to determine this). You finally get to do some math here that makes sense… you merely average these numbers. “Am I done?” you naively ask. No! You’ve still got to multiply this number by 0.96 and then truncate to the tenths of a number. Why 0.96? That is called the Bonus for Excellence and is there to make it easier for golfers closer to scratch to score better after handicap adjustments.

I’d write about more stupid math but I’ve already got a headache. Maybe later.

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