The USGA has created a rating system to help golfers understand the difficulty of each course. It is called 'slope,' and it takes into account both how difficult it will be for scratch players (course rating) as well as those who make bogeys on their round (slope).
The minimum slope rating is 55 and the maximum isn't any higher at 155. The higher your course's angle, in other words how steeply it slopes off from the level ground, the more difficult will be for those who play that particular layout versus someone with an easier course. In 18 holes on average golf courses have a max allowable slope of 113; however, this number may vary depending upon what type of calculation methods you use when computing one’s handicap score.
Now that we know what slope rating is, you may be wondering how a golf course's slope affects your game. The first thing most golfers do when they reach the green is check for this information and it can usually be found in every tee box on scorecards with an average of 113 slopes-or lower than that if there are plenty of flat areas.
If we know the average slope rating of a golf course is 113, then any golf course with higher slopes should be taken more seriously. If you see that there are some tee boxes that have ratings over 100 degrees and others at 20-30 degree slants; don’t get intimidated by this change in difficulty.
Course slope is a figure that indicates the difficulty of a course in relation to an even-par golfer. A 90-degree slope would be considered very difficult for someone who averages 18 bogeys per round, but if they only score one or two over par then their scores will come out lower than what you'd expect based on average stroke play conditions.
The Slope rating is impacted by a number of factors, including forced lay-ups. If the Scratch golfer has to make an approach shot due to any one or more obstacles on their course (water hazard, severe dogleg), this will increase their slope score because you add extra yardage with an out and back layout rather than just hitting straight across like most holes do in resort courses where there isn't much else about them that makes it interesting other than how long they take for instance.
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