Detailed explanation of terms used in measuring golf course difficulty
What is a USGA Course Rating™, Slope Rating® and Bogey Rating™?
These terms, defined by USGA, are essential when rating the difficulty of a course. (Terms are trademarked by USGA www.usga.org).
Course Rating: A USGA Course Rating is the evaluation of the playing difficulty of a course for a Scratch Golfer under normal course and weather conditions. It is expressed as the number of strokes taken to one decimal place (eg 72.5), and is based on yardage and other obstacles to the extent that they affect the scoring difficulty of the Scratch Golfer.
Scratch Golfer: A male Scratch Golfer is a player who can play to a course handicap of zero on any and all rated golf courses. A male Scratch Golfer, for rating purposes, can hit tee shots an average of 250 yards and can reach a 470-yard hole in two shots at sea level.
A female Scratch Golfer is a player who can play to a course handicap of zero on any and all rated golf courses. A female Scratch Golfer, for rating purposes, can hit tee shots an average of 210 yards and can reach a 400-yard hole in two shots at sea level.
Bogey Rating: A Bogey Rating is the evaluation of the playing difficulty of a course for a Bogey Golfer under normal course and weather conditions. It is expressed as the number of strokes taken to one decimal place (eg 92.1), and is based on yardage and other obstacles to the extent that they affect the scoring difficulty of the Bogey Golfer.
Bogey Golfer: A male Bogey Golfer is a player who has a course handicap of approximately 20 on a course of standard difficulty. He can hit tee shots an average of 200 yards and can reach a 370-yard hole in two shots at sea level.
A female Bogey Golfer is a player who has a course handicap of approximately 24 on a course of standard difficulty. She can hit tee shots an average of 150 yards and can reach a 280-yard hole in two shots.
Slope Rating: The more difficult a course is, the greater the discrepancy is between the scores of stronger and weaker players. So, Slope Rating is a term trademarked by the USGA that indicates the measurement of the relative playing difficulty of a course for Bogey Golfers, compared to Scratch Golfers. Course Rating tells Scratch Golfers how difficult the course will be; Slope Rating tells Bogey Golfers how difficult it will be.
Simply put, Course Rating tells the best golfers how hard a golf course actually plays; Slope Rating indicates how much harder the course plays for ‘regular’ (meaning not among the best) golfers.
It is computed from the difference between the Bogey Rating and the Course Rating multiplied by a constant factor (5.381 for men or 4.24 for women) and is expressed as a whole number.
The minimum Slope Rating is 55 and the maximum is 155 (slope does not relate specifically to strokes played as Course Rating does). When the Slope Rating system was first put into effect, the USGA set the slope for an ‘average’ golf course at 113; however, not many 18-hole golf courses have Slope Ratings that low. Some do, but the real-world average is higher than 113. (However, a slope of 113 is still used in certain calculations within the handicap system.)
Why calculate a Slope Rating?
The most important role of slope is levelling the playing field for players of different skill levels. For example, let’s say Player A and Player B average 85 strokes each for 18 holes. But Player A’s average is established on a very difficult course (say, a Slope Rating of 150), while Player B’s average is established on a much easier course (say, a Slope Rating of 105). If handicaps were simply estimates of golfers’ average scores, then these two players would have the same handicap index. But Player A is clearly the better golfer, and in a match between the two Player B would clearly need some strokes.
Slope Rating allows the handicap index to reflect these factors. Because he plays on a course with a higher Slope Rating, Player A’s handicap index will be lower than Player B’s (when it is calculated using the slope ratings), despite the fact that they both average scores of 85. So when A and B get together to play, B will get those extra strokes he needs.
Slope Rating also allows golfers to go to different golf courses and adjust their handicap index up or down depending on how difficult each course plays.
Slope is primarily used in the United States, but golf associations in other countries are beginning to adopt slope or similar systems.