Golf course-slope rating?

The slope rating of a golf course is a term developed/branded by the USGA. This is a difficulty measurement of a golf course for bogey or average golfers relative to the course rating. The slope does not relate specifically to your number of strokes played like the course rating. Slope rating is a factor in the calculation of handicap, and is also used to determine the course handicap. Like course rating, slope rating is generally determined for each set of tees on a course. Some higher end courses provide on the scorecard separate slope rating for each set of tees I think slope was developed as means of leveling the playing field for players of different skill levels. I hope that helps.

A course is rated for both scratch players and bogey players. The "course rating" ,the one you see on the scorecard, is the rating for the scratch golfer. The larger the gap in the two, the greater the slope. Typically a course with a high slope rating has forced carries, deep bunkers, long holes, lots of water, etc.

Good answers so far in general. Just add that the USGA's definition of a bogey golfer is one who hits an average drive around 200 and can get on the green in two on a 370yrd par 4 (I think) and shoots 20 over par. I think, then, they take this into consideration. So, adding to the other comments, I think it might also matter where the bunkers are. If the fairway bunker from one set of tees is 250yds away, it might not have as high a slope as the same hole with the same bunker at 190. The assumption is that the 190 bunker is in play for a bogey golfer. Why does this matter? Because if are like me a year ago, I was a 20 hcp but had a 240 drive and couldn't putt. So the slope wasn't highly correlated to my play. A hole might play harder or easier than intended because I didn't fit the bogey golfer model. They also take into consideration trees that might get in the way, distance to carry the bend on doglegs, etc. I think Dean Knuth developed the idea of slope. There is actually a detailed manual they have that details the slope and it's relationship to ratings and handicaps etc.

the hazards raise the slope, courses with a lower slope tend to have less hazards or bunkers etc