In the UK, South Africa and Republic of Ireland, a "scratch score" system was previously in place in order to rate golf courses and be fair to golfers of varying ability, and to make allowances that golf courses may play "easier" or "harder" than par, overall, to the amateur field.

The slope rating is the USGA mark that indicates the measurement of the relative difficulty for a bogey golfer compared to the golf course rating. Slope rating is computed from the difference between the bogey rating and the golf course rating.

The course rating (SSS) and the slope rating are used to calculate the handicap differential which is used to adjust a player's score in relation to par according to the slope and rating of the golf course.

Handicap differential = ( players score -golf course rating) × 113 / (slope rating)  then rounded to the nearest tenth.

The bogey rating is the USGA evaluation of the playing difficulty of a golf course for the bogey golfer. It is based on yardage, effective playing length and other obstacles to the extent that affect the scoring ability of the bogey golfer.