Rating of course, rating of slope, and handicap of course

In the United States, officially rated golf courses are described by course and rating of slope. Rating of course is a number (typically between 67 and 77) that is used to measure the average "good" score that a scratch golfer may attain on the course. A rating of slope in contrast, is a number (typically between 55 and 155) describing the relative difficulty of a course for a bogey golfer compared to a scratch golfer.

A handicap of course indicates the number of strokes that a golfer receives at a particular golf course. It can be thought of as an adjustment to a golfer's handicap that takes the difficulty of a golf course into account. It is the number of strokes that should be deducted from a golfer's gross score to determine net score.
Playing condition adjustment

Since golf is a game that is played outdoors, weather or other conditions can significantly affect a player's scores. As such, in an effort to more accurately represent a player's scores, an adjustment, referred to as the Playing Conditions Calculation (PCC), based on playing conditions for the course is included. This involves factoring in a number, ranging from -1 (when conditions make the course easier) to 3 (when conditions make the course more difficult), into the score differential calculation, depending on the conditions of the course for the given day.

For example, if the conditions on a course are relatively bad on a given day (e.g. rain and heavy wind), the player's score can be adjusted to reflect that, given a day with relatively better weather conditions, the player's score would likely have been better, and the score will be automatically adjusted using statistical procedures to more accurately reflect these conditions. The same is also true in particularly good weather conditions that could cause a player's scores to be better than they otherwise would be.

Because this adjustment is dependent on a given day, and since it is calculated automatically, it is important that players submit their scores on the actual day of play so that the PCC will be applied to their score on the correct day. This calculation is intended to be conservative and will not be applied unless there is strong statistical evidence that it is necessary.
Index of Handicap Calculator

Use this calculator to compute the index of handicap for a golfer given data from at least 54 holes (3 rounds of 18-holes) of playing data. When filling the form, please provide either an 18-hole or 9-hole score. Do not provide both. The playing condition adjustment is an optional value between -1 and 3. If left blank, it will be treated as 0.

Slope

Under Slope, a golfer’s playing handicap on any given day will be determined according to the difficulty of the tees or course to be played. Golf Australia believes that this will be fairer than our current one-handicap-fits-all-courses method.

What are the features of slope?
• Every set of tees on every golf course around the country will have a Slope Rating which has been determined in accordance with the new course rating system. The maximum Slope Rating is 155 (most difficult) 
and the minimum is 55 (least difficult). The Neutral Slope Rating is 113. Every set of tees will also have a Scratch Rating.
• GOLF Link will calculate a nationally-standardised handicap index for every player and this will be called the GA Handicap.
• A GA Handicap will be calculated by using the best 8 of a player’s most recent 20 scores (ie best 8 of 20, x 0.93). However, every score in every player’s score history will first be standardised by GOLF Link against a Slope Rating of 113. As a result, the GA Handicap will reflect a golfer’s ability on a course which has the neutral Slope Rating of 113.
• The GA Handicap is not intended for use as a playing handicap. It is to be used in conjunction with the Slope Rating of the set of tees being played to calculate a golfer’s playing handicap for the day, and this will be called the Daily Handicap.
• It is the GA Handicap that will be displayed in a player’s GOLF Link record on www.golflink.com.au.

How will Slope make things fairer?

Generally speaking, a high marker finds it harder to adjust to a difficult course than a low marker does. Slope adjustments will play a balancing role. For example, if the Black Tees are harder than the White Tees, a high -marker may play the Black Tees off a handicap of 28 and the White Tees off 24. The Elite player finds it easier to adjust, so they may play the Black Tees off 4 and the White Tees off 3. Golf Australia believes this is fairer than having the difference between the elite player’s handicap and the high-marker’s handicap always stay the same.

Every time before playing a round, a player should check what their daily handicap will be for that round. How can they do this?

• Different clubs will use different methods to communicate Daily Handicaps to golfers. Examples of different methods include via the use of existing club computer systems, and via direct printing on to score cards. Some clubs will provide easy-to-use Daily Handicap look-up posters.
• The GA website and the GOLF Link website will feature Daily Handicap calculators.

A player will play off their daily handicap when they visit another club, but what handicap do they use at their home Club?
• Whether at an away club or at the Home Club, the player will need to check their Daily Handicap for the tees they are playing from and play off this handicap.
• Home Club Example: A player with a GA Handicap of 22.3 when playing off the White Tees (eg Slope Rating of 119) at their Home Club will play off a Daily Handicap of 23; and when they play off the Blue Tees 
(eg Slope Rating of 136) will play off a Daily Handicap of 27. (Note: The same calculations would apply if the example was for an away club).

What is the formula that Golf Link will use to calculate a daily handicap?
Daily Handicap = GA Handicap x Slope Rating ÷ Neutral Slope Rating 
(ie 113)
1. Calculation of Ga handicap – Best 8 of 20, Multiplied by 0.93 [already in effect]*
To calculate a player’s GA Handicap, GOLF Link does the following:
• Firstly it identifies their most recent 20 scores (these are displayed on www.golflink.com.au),
• It then averages the Differentials from the best 8 of them (Differential is the calculation of the player’s score against the course rating; it is the value listed in the ‘Played To’ column on www.golflink.com.au),
• Finally it multiplies this average by 0.93. The resultant figure is the player’s GA Handicap.

Example 2 

Adam’s GA Handicap is 18.4 and he plays from a set of tees with a 
Slope Rating of 95.
18.4 x 95 ÷ 113 = 15.
Adam’s Daily Handicap is 15.

Example 1 
Adam’s GA Handicap is 18.4 and he plays from a set of tees with a 
Slope Rating of 128.
18.4 x 128 ÷ 113 = 21.
Adam’s Daily Handicap is 21.