Understanding Course and Slope Rating
Course Rating is one of the key services that the Maine State Golf Association provides to its member clubs. Although not as visible as the handicap/GHIN service, course ratings go hand-in-hand in assuring that the handicap indexes issued at your club and throughout the state are accurate. We are proud of our teams of volunteers statewide who study the manuals and work to become proficient raters. MSGA staff members also attend national Course Rating calibration seminars to assure that our raters are following the USGA’s best practices and are on the same page with other raters nationwide in their calculations.
The purpose of this page is to tell you more about the Course Rating process. We will explain what happened when your course was rated and how the forms and manuals were reviewed. Our goal is to give you a better understanding of the difference between a USGA Course Rating, Bogey Rating and a Slope Rating. We hope to leave you with an understanding of how all these numbers work together to assure that your members’ handicap indexes are accurate. And finally, we will give you some information that will help you set up your course so that the ratings issued here remain accurate until we visit your club for a future rating.
If you have questions about the information contained here or about your new ratings, please be in touch.
When and how are golf courses rated?
New courses have to be rated again within five years of opening because courses usually make significant changes during the first few years. After that, the USGA requires courses to be rated every ten years. In addition, a course that has undergone significant changes should be rated again.
So how are golf courses actually rated? Each hole is rated individually. Contrary to what many golfers believe, the ratings are based largely on mathematical calculations as opposed to subjective judgments. Ninety-five percent of the calculations are based on measurements taken while going around the golf course. While each hole is rated in 14 different categories, the most important by far is yardage, starting with how far the average player is expected to hit his tee shot. According to the USGA guidelines, the scratch golfer hits his tee shot 250 yards and can reach a 470 yard hole in two shots. The bogey golfer’s tee shot goes 200 yards and he can reach a 370 yard hole in two shots. (The comparable numbers for women are: scratch 210/400 and bogey – 150/280) From these guidelines the landing areas can be determined and the rating team can take their measurements. The raters then ascertain the width of the fairway, the proximity of obstacles such as bunkers, out-of-bounds, water, heavy rough or trees and the seriousness of the obstacles. The topography of the landing area is also viewed. Basically anything that confronts the player is gauged for its potential effect on the shot.
Once the team gets to the green, they measure the dimensions of the green and calculate the percentage of the green that is surrounded by bunkers, how deep those bunkers are, and again the proximity of hazards and also what the terrain around the green is like. The length of the approach shot into the green matters, along with what the characteristics of the green are.
After the team finishes on the course the numbers are plugged into a computer which analyzes the numbers and comes up with the new course rating. The Course Rating indicates what a scratch golfer should shoot on a good day. A bogey rating is also calculated, which many golfers are not aware of. This number quantifies the difficulty of the course for the bogey golfer and is used to calculate the slope rating. The course rating and the slope rating form the basis of the USGA handicapping system, but they are sometimes misunderstood.
Many golfers believe that the slope rating measures a course’s difficulty, when in fact it is a measurement of how much more difficult that specific course is for the bogey golfer than for the scratch golfer. The slope rating is a number between 55 and 155, with 113 being the average.
THE RATING PROCESS
Effective Length Corrections
The most important element of an accurate course rating is the correct yardage of each hole. Using a laser the rating team compiles all its measurements which may then be adjusted to determine the effective playing length of the hole. The possible adjustments are:
- Roll --- Does the ball get its normal amount of roll off the tee shot?
- Elevation --- Is the hole uphill or downhill from tee to green?
- Dogleg --- Does the hole have a bend, forcing a player to hit less club to the pivot point? Or, can a player shorten the hole by cutting the corner?
- Lay-Up --- Does the player have to hit less club to stay short of a severe obstacle that cannot be carried?
Roll, Elevation, Dogleg and Forced Lay-up are all factors that can impact the playing length of the hole.
The following obstacle factors are evaluated for each landing area for the scratch and bogey golfer.
- Topography --- The difficulty of the stance in the landing areas is evaluated and combined with any elevation change for the shot into the green.
- Fairway --- Each landing area width is measured and adjustments may be made ifthe ground tilts or if there is an obstacle that makes the fairway play narrower than it measures.
- Green Target --- How hard is it to hit the green? The rating value is usually a combination of the size of the green and the length of the shot neededto reach it and how visible the green is from that approach shot area.
- R&R --- (Recoverability and Rough) If you miss the green or the fairway, how hard is it to recover.
- Bunkers --- Bunkers are evaluated around the green for coverage and depth. Fairway bunkers count, but are not rated as high as greenside bunkers.
- OB/Extreme Rough --- The distance from the center of the landing zone to out-of-bounds or extreme rough is measured and whether there are factors such as cart paths or fences that could influence where the ball goes.
- Penalty Areas --- Lateral and carry water hazards are considered for each affected shot. The shot length to safely carry the water or the distance to the lateral water is used to determine the obstacle value. Water that comes into play on more than one shot adds to the rating value.
- Trees --- Trees are evaluated based on the length of the shot and the possibility of recovery from the trees.
- Green Surface --- The speed of the green is determined and the green is evaluated for surface contours and tiers.
- Psychological --- The value for the mental effect of playing around all the above obstacles is purely mathematical and is calculated by the computer based on the previous factors.
When will the MSGA rate your course again?
The MSGA will normally contact a club to set a date to re-rate your course every 10 years. This time period is established by the USGA and assures that our member clubs have current and accurate USGA ratings at all times. Between scheduled ratings, your club might find it necessary to make changes to your course that could affect the playing difficulty of the course.
Temporary ChangesAll clubs go through periods of change or temporary repair to holes on the golf course. Because the membership usually continues to play the course while this work is being done, it is sometimes necessary to make adjustments to score posting procedures. Please review Section 4 of the USGA Handicap Manual which explains the process for posting scores when a hole is “not played” or not completed.
Please contact the MSGA for advice on how to handle any problems with scores while doing substantial work on the course.
If your club plans to make permanent changes to the course, we ask that you contact us while work is under way so that we can get your course scheduled for any necessary re-rating work.
Assuring That Your USGA Course/Slope Ratings Remain Accurate
It is important that our member clubs know that their ratings are based on the measured length and playing difficulty of the course under normal conditions. Placement of tees and holes should be balanced each day to assure that the overall length of the golf course remains close to the yardage as measured by the rating team, from the middle of each teeing ground to the middle of each green.
Clubs will usually establish a pattern for rotating tee locations and hole locations. On average, a practice of 6 tees forward, 6 tees middle and 6 tees back, along with similar placement of hole locations will assure that the overall yardage of the course remains close to its measured length.
Following are some examples of how improper length set-up of a course can impact a rating, and ultimately your members’ handicaps:
Tee Placement or Hole Locations:
Adding 10 yards on each hole adds 180 yards to the course, meaning an increase of .8 (1.0 for women) to the Course Rating and 2 points to the Slope Rating. The reverse would be true if the course was shortened by 180 yards.
Creating Forced Lay-ups:
A severe obstacle that cannot be carried can add as much as 50 yards on a hole, changing the course rating approximately .2 strokes.
Changes to Obstacles:
Changes to the obstacles that were evaluated as part of the rating process will have less of an impact than a change in yardage, but are important as well. Some areas to monitor are as follows:
- Fairways --- Changes to the mowing pattern and width of the fairway in the landing areas.
- Rough --- Raising or lowering the height of the rough.
- Out of Bounds --- Moving the OB stakes closer or further from the landing areas or the greens.
- Bunkers --- Changes to the number or depth of bunkers, especially around the greens.
- Green Surface --- Changing mower height or cutting frequency to change the speed of the greens.
It is important that course setup and day to day maintenance is consistent with what was observed and measured by the Course Rating team. Otherwise, inaccurate ratings can quickly result in inaccurate USGA Handicap Indexes for your members.
A suggestion when deciding what tees to play…
The USGA Course and Slope Rating can cause a lot of confusion. Many clubs feel that a high Slope Rating is a badge of honor or a basis for bragging rights, indicating a difficult golf course. In many cases, they are only half right.
The difficulty of the course for each set of tees is best indicated for the scratch golfer by the Course Rating. That is the score that a good player hopes to make about 25% of the time. The Bogey Rating, which historically has not been published, represents what a bogey golfer hopes to score, again about 25% of the time. The Slope Rating is a number that represents the relationship between those two numbers.
The easiest way to explain this concept is to say that as a golf course gets harder for the scratch golfer, it generally gets harder at a faster rate for the bogey golfer. As a player’s index goes up and the Slope Rating of the course he is playing goes up. For a low handicap golfer, his course handicap hardly changes as the Slope goes up – only going from a Course Handicap of 5 to 6 as the Slope Rating went from 112 to 142. For the player with an index of 35.0 however, the change is dramatic. He gains 9 shots – from 35 to a Course Handicap of 44! In other words this high Slope Rating says to the Bogey Golfer, “Don’t go there – you won’t have fun!” It means there are severe carries and other substantial obstacles that present unrealistic challenges for the higher handicap golfer.