A handicap index is not a statistical scoring average-it is the basic measure of a player's scoring potential. It is based on the performance of a player over 20 rounds of golf. Each time a score is posted, the course rating and slope for the tees played is used to calculate a differential. This differential is the measure of the player's performance on that particular course. By relating performance to course difficulty rather than raw scores, players of unequal abilities can compete on a level basis.

Since players are not always at their best or worst, the differential is averaged using the 10 rounds with the lowest differential from the last 20 rounds posted. A player's index is 96% of this average differential.

The handicap index is not the course handicap that players use to determine their net score. The index along with the slope for the tees played is used to calculate the player's course handicap. Each course has a set of sheets posted showing the handicap to be used for the tees played based on a player's handicap index.

In order to obtain an index, players must have a minimum of 5 posted rounds. With only 5 rounds, the index is 96% of the lowest differential. As the number of rounds increases, the number of differentials included in the average increases until 20 rounds are posted. From that point, the oldest round is removed when a new round is posted and the 10 lowest differentials are used to calculate the index.

The handicap indices are recalculated every month. The scores are collected by the SCGA on the third Monday of each month. If a score is posted after that point, it won't be used until the next month. The computer systems pass the information between courses. Although it is not always the case, scores are collected and redistributed each night. This means that a score posted at an away course on Monday could be expected to show up on all computers no earlier than Wednesday. Even so, the score is not used for the current index until the end of month update.

The trend index which appears on the computer is a running handicap index average. It is not normally used for calculating handicaps for events.

It is important that players post all rounds played. Many players decide not to post bad rounds. This actually hurts you. A bad round may be embarrassing, but it is as much a part of your game as a good round. If you only post good rounds, your handicap index will be lower than your true playing potential.

You should post any round of golf you play. If you do not complete the round, you should post an 18 hole score if you play 13 or more holes. If you play less than 13 but more than 7, post a 9 hole score. Take net par for any holes not played. If you don't finish a hole, take the score you would "most likely have gotten." If you picked up a 10 foot putt, you might assume it would have taken two putts to finish.

You also must adjust your scores for bad holes. This is known as "equitable stroke control" (ESC). It limits 0-9 handicaps to double bogey on any hole, 10-19 to 7 on any hole, 20-29 to 8 and 30+ to 9. This is the adjusted score you post. Note that your "handicap index" does not determine these ESC score posting limitations. It is your "course handicap" that applies. For example, a player with a handicap index of 8.9 may have a course handicap of 10. If that player scored 7 on any hole, he would be able to post it without adjustment--even a par 3.