A differential is a by-product of the course rating and slope rating. A handicap differential is the difference between a players adjusted gross score and the course rating of the course on which the score was made, multiplied by 113, then divided by the slope rating from the tees played and rounded to the nearest tenth. Once the differentials are calculated the best 10 of the last twenty are used to establish an index. The next steps are as follows; average the differentials being used, multiply the average by .96* and delete all numbers after the tenth's digit. Do not round off to the nearest tenth. * Bonus for excellence is the incentive built into the USGA Handicap System for player to improve their golf games. It is the term used to describe the small percentage below perfect equity that is used to calculate Handicap Indexes (96%)
