HANDICAP ADVICE: Handicap Differential
Q: Whenever I post a score I notice there is a column called 'differential' next to it. What does that mean?
A: The differential reflects your score in relation to course difficulty. If you shot 88 on two different courses, the course with a higher Slope and Course Rating would give you a lower differential than the easier course. Better scores on harder courses will lower your Handical Index more substantially.
By DEAN KNUTH, Golf Digest Contributing Editor. Knuth, the former senior director of the USGA handicap department, invented today's Course Rating and Slope system.
From Golf Digest September 2012, page 54