WARREN, PA — Slope. It doesn't make much sense, given what it means, does it? Why did the USGA choose the term "slope" to represent the relative difficulty of courses for bogey golfers?

When the USGA added slope rating to the pre-existing course rating, in the early 1980s, it did so because of something that had always been obvious. The more difficult a course is, the greater the descrepancy is between the scores of stronger and weaker players.

The course rating system did not account for that factor; slope does.

Imagine two players, Player A (Kelly Smith) and Player B (Greg Garrett). Kelly is a six handicapper, Greg is a 16 handicapper. On a course of average difficulty (slope of 113), both players are likely to play close to their handicaps.

But as course difficulty increases, Garrett's scores will rise faster than Smith's. On a course with a slope of 135, Greg might need an additional 10 strokes, while Smith might only need an additional 3.

Now, imagine that descrepancy plotted on a graph. The graph lines of both players A and B would rise as the course difficulty increased - but the line of Garrett would rise at a much steeper angle than that of Smith.

The slope of a weaker player's scoring graph is steeper than that of a stronger player's. And there you go. The term "slope" - referring to relative steepness of the graph line of a weaker player's scores - was chosen to represent the USGA's new method of rating course difficulty for bogey golfers.

Hey, they had to call it something.

Course rating and slope rating are calculated for a course on the basis of a visit to the course by a USGA rating team.

The rating team will spend time with the course's staff going over the course and will spend a lot of time on the course taking measurements of various things. The USGA recommends that the rating team play the course either before or after the rating visit, too.

Based on the information gleaned during the visit(s), the course rating and course slope will be calculated, certified by the appropriate overseeing golf associations and given to the club, which then posts the ratings on its scorecard and elsewhere.

A bogey golfer, in this use, is defined by the USGA as a male golfer with a handicap index of 17.5 to 22.4, who hits his drives 200 yards and can reach a 370-yard hole in two; and a female golfer with a handicap index of 21.5 to 26.4, who hits her drives 150 yards and can reach a 280-yard hole in two.

The USGA will also issue a "bogey rating," something many golfers don't know exists for each golf course. The bogey rating is similar to course rating, it's just an evaluation of how many strokes a bogey golfer will take to play the course rather than an evaluation of strokes needed for scratch golfers.

And the bogey rating has in important role: it is used in the calculation that produces the slope rating.

Slope, remember, is a number representing the relative difficulty of a course for bogey golfers compared to scratch golfers. The calculation that determines slope is this: bogey course rating minus USGA course rating x 5.381 for men or 4.24 for women.

The "effective playing length" and "obstacle stroke value" are the determining factors in course rating and bogey rating.

Effective playing length is exactly that - not the actual yardage on a hole or a shot, but how it actually plays. Is there a downslope that will add yards? An upslope? Is the course at altitude, which will produce more length? What's the height of the fairway grass, which will affect roll? Are there forced lay-ups?

Obstacle stroke value is a numerical rating of the difficulty presented by obstacles on the course. The course is rated in 10 categories: topography; easy or difficulty of hitting the fairway; propability of hitting the green from the fairway landing area; difficulty of bunkers and probability of hitting into them; probability of hitting out of bounds; how much water will come into play; how trees affect play; speed and contouring of the greens; and the psychological effect of all these things.

The rating team will look at all these things for both scratch golfers and bogey golfers, and from every set of tees. And then follow the USGA's four formulas (male scratch golfer, female scratch golfer, male bogey golfer, female bogey golfer), some adding, subtracting, multiplying and dividing, and produce its numbers.

And you thought rating a course was easy!