A technical term in golf, slope rating is the United States Golf Association (USGA) mark, indicating the measurement of the relative difficulty for a bogey golfer in comparison to the course rating.
For the aspiring Tiger Woods, Jyoti Randhawas, and Phil Mickelsons, slope rating is a very common term. They probably breathe these terms day in and day out while practicing. But to get a better idea of what a slope rating is, we first need to know what is course rating, scratch golfer, and bogey golfer.
What is Slope Rating?
According to the USGA, a scratch golfer is defined as "An amateur player who plays to the standard of the stroke play qualifiers competing in the United States Amateur Championship. The male scratch golfer hits his tee shots an average of 250 yards and can reach a 470-yard hole in two shots. The female scratch golfer can hit her tee shots an average of 210 yards and can reach a 400-yard hole in two shots." In short, a golfer who can shoot par or better. Likewise, bogey golfers are defined by USGA as "A player with a USGA Handicap Index of 17.5 to 22.4 strokes for men and 21.5 to 26.4 for women. Under normal situations the male bogey golfer can hit his tee shot 200 yards and can reach a 370-yard hole in two shots. Likewise, the female bogey golfer can hit her tee shot 150 yards and can reach a 280-yard hole in two shots. Players who have a Handicap Index between the parameters above, but are unusually long or short off the tee are not considered to be a bogey golfer for course rating purposes."
Now that this is clear, it will be easier to explain slope rating. It refers to the measurement of a course, especially for bogey golfers, relative to the course rating. Now, this course rating indicates the scratch golfers, how difficult the course will be for them. And it tells bogey golfers how tough it will be for them too. It is a determinant in the calculation of a handicap index, and it is also used to know how much the course handicap is. Bogey rating is the assessment of the playing difficulty of the course, and this, along with the course rating determine the slope rating. It is calculated from the difference between the course rating and the bogey rating. The minimum value is 55m and maximum is 155. This is very important, because then the golfer can decide his game plan and the swing that he needs to have.
How is Slope Rating Determined?
Slope rating for a course is determined by a USGA rating team on the basis of their visit to the course. Normally, this team spends a lot of time on the course and take measurements of a lot of things. The USGA ideally suggests that the rating team play the course either before or after the rating visit as well. Then, based on the information gathered during the visit/s, the course slope and rating is calculated, which are certified by the concerned overseeing golf associations, and then the statistics are passed on to the club. Later, the club posts the ratings on its scorecard and elsewhere. Previously, the length of the course was a major consideration in determining the slope rating. Consequently, longer the course, the higher the rating. Now, obstacles, along with the distance are an important component of this rating.
All said and done, while the rating team is on its visits, and is assessing the course for determining the golf course slope, they have to step in the shoes of bogey golfers as well as scratch golfers. The formula for slope rating is: bogey course rating minus USGA course rating multiplied by set factor, i.e., 5.381 for men or 4.24 for women.