History
The United States Golf Association (USGA), golf's ruling body, established the first handicap system in 1912. This was initially based upon the top three scores a golfer had for the season and remained that way for many years to come. Early improvements to handicapping involved rating different courses as to their difficulty thus requiring an accurate system to be implemented. A change to the way in which the golfer's handicap was calculated or how the courses are rated was a continuous process throughout the years, including the adoption of the slope rating system in the 1980s. Currently, the USGA handicap system is in place for over 4.5 million golfers worldwide.

Purpose
The USGA Handicap System was designed to promote fairness during competitions by allowing men and women of varying abilities and who may play from different sets of tees to play on an equal basis. For example, it would possible for a player who has an average score of 95 to compete fairly with a professional. Without such a handicap system, this would be impossible. It is important to realize that the USGA developed this formula to tabulate handicaps only through licensed golf clubs and not directly to individual golfers themselves. The definition of a golf club is "an organization of at least ten individual members that operates under bylaws with committees (including a Handicap Committee) to supervise golf activities, provide peer review, and maintain the integrity of the USGA Handicap System."

Handicap Index
How do you obtain a handicap index. First, you must join a golf club and start posting all your adjusted gross scores, which we will explain later. Once you have posted a minimum of five scores, the club will be eligible to issue that player a handicap index. A more accurate handicap index involves posting more scores. Ideally, the handicap index is based on the 10 best scoring differentials from the most recent 20 scores. However, the system allows fewer. The chart below will help explain this better.

Number of acceptable scores	Scoring differential(s) to be used
5 or 6	Lowest 1
7 or 8	Lowest 2
9 or 10	Lowest 3
11 or 12	Lowest 4
13 or 14	Lowest 5
15 or 16	Lowest 6
17	Lowest 7
18	Lowest 8
19	Lowest 9
20	Lowest 10

The method in which the USGA calculates a handicap index is as follows. From the table above, you select the proper number of handicap differentials to use. What exactly is the handicap differential? It is derived from fours factors: adjusted gross score, USGA Course Rating, Slope Rating and the number 113, which is the standard difficulty level. The next step is to determine the handicap differential for each round that is posted.

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

For instance, see the scorecard below in which Ted is posting a score from his latest round playing from the white tees. The course rating and the slope rating can be found on the front of the card. In this case Ted has adjusted gross score of 91 on a course with a USGA Course Rating of 71.9 and a slope of 134.

Adjusted Gross Score - USGA Course Rating: 91 - 71.9 = 19.1
Difference x Standard Slope Rating: 19.1 x 113 = 2158.3
Result / Slope Rating: 2158.3 / 134 = 16.11
Handicap Differential (rounded): 16.1

Each golf handicap differential to be used will then be averaged. After which the average is multiplied by 0.96 and all numbers after the first decimal place are deleted (i.e. 18.1935 = 18.1) to establish the handicap index. For the record, there is a maximum handicap index. For men it is 36.4 and for women it is 40.4.

Don't worry about all of this math that is the responsibility of the golf club maintaining your handicap. Plus there is software available to assist the process and reduce the likelihood of any errors. The USGA has a handicapping service called GHIN, short for Golf Handicap and Information Network that computes the handicap of more than two million golfers worldwide at clubs that participates in the network.

Posting a Score
It is the responsibility of the player to post all acceptable scores. Failure to do so "does not observe the spirit of the USGA Handicap System." Why not post all your scores? Well some golfers only turn in their high scores to inflate their handicap to increase their odds of winning. This practice is called "sandbagging" and it is highly frowned upon by fellow golfers.

In addition, some golfers may not be aware they can post a round. For instance, the golfer was playing in the evening. After Hole #16 it was too dark to play and therefore was unable to finish the round. In cases like this, the golfer would simply fill in the score he or she may have had using the handicap rating of the holes on the scorecard. For instance, if the golfer had a handicap index of 9 and the Par 4 17th Hole had a handicap of 16, then the player would post a 4 for that hole. However, if the Par 5 Hole #18 was the number 1 handicapped hole on the course, that player would receive one handicap stoke and should record a 6 as the score.

The only times when a score is unacceptable should not be posted is when any of the following apply:

• Fewer than 7 holes were played

• The majority of the holes were not played in accordance with the principles of the Rules of Golf

• Number of clubs is restricted for competition, such as an iron only format

• Score was made on a course that did not have a USGA Course and Slope Rating

• Player carries or uses non-conforming clubs or balls

• The use of an artificial devise under Rule 14-3 in the Rules of Golf

• The course was played during an inactive season established by the governing golf association

The last stipulation is controlled by the local golf association to determine when scores can be accepted. For example, in Ohio during the month of January, most golf courses are not open. Even if they were open on a particular warm day, the course would not be set up under normal conditions therefore the score should not be counted. However, if that golfer was playing in Florida during that same period as the season is active all year round he or she should be posted at his or hers golf club in Ohio.

In posting a score, it may be necessary to adjust the score before posting it. For example, you have a bad hole (or maybe two). The USGA Handicap System is set up to reflect the scoring potential of a golfer. Therefore an "Equitable Stroke Control" was implemented to make the handicap more representative. This puts a cap on the maximum score a player can shot based upon their handicap. The following table illustrates how it works.

Course Handicap	Maximum Number On any Hole
9 or less	Double Bogey
10 through 19	7
20 through 29	8
30 through 39	9
40 or more	10

For example, Ted has a handicap index of 18. On one nightmarish hole he scored a 12. The most strokes he could write down would be a 7. Therefore he reduces his score by five strokes as his adjusted gross score.

Course Handicap
The player's handicap index may actually be different from the course handicap as each course is rated differently, plus which set of tees you play from would have an affect. To convert to the course handicap use the following:

Course Handicap = Player's Handicap Index x 113 / Slope Rating
Then rounded to the nearest whole number

Hopefully you gain a better understanding of the USGA Handicap System. There are many more rules governing the way in which the handicapping system works. For a further explanation, consult the USGA Handicap System Manual or speak with a member of your golf club's handicap committee.