Golf Digest, October, 1988, page 14-15

Lionel Callaway, the creator of the "Callaway system" for devising a handicap, died recently at age 93. His one-round handicapping method, also called the "Pinehurst system" because that's where Callaway lived, provided a service by allowing golfers who didn't have an official U.S. Golf Association handicap to approximate one. It was arrived at by subtracting a total of your worst holes that varied according to what you shot.

But recent research by the USGA concluded that his system was inequitable. Dean Knuth, USGA handicapping director, ran millions of scores through his Golf Handicap and Information Network (GHIN) center in Far Hills, N.J. and found the Callaway system merely "compressed the range of net scores to give the illusion of a close competition," but in actuality the lowest gross score still won.

"Philosophically," adds Knuth, "you shouldn't handicap based just on the round you're playing." Knuth and the USGA Handicap Research Team went to work to find what number in a golfer's last 20 scores most closely correlated to his USGA Handicap. VOILA! They discovered your second best score of the past year on a course with a par of 70 or higher as the "magic number" that comes remarkably close to providing an accurate handicap, within plus-or-minus one stroke. All you do is take that score, subtract 70 if you're a man, 73 if you're a woman, and that's your handicap for the day (e.g., 85-70=15).

This new system is known as the Honest Reference Technique (HRT), because it assumes a golfer is turning in honest scores. The USGA is replacing the Callaway system with HRT in its Golf Committee manual's guidelines on "handicapping the unhandicapped" effective in 1989.