This article is from the Golf FAQ, by marcelo@nntpserver.Princeton.EDU (Marcelo A. Gallardo) with numerous contributions by others.
The Callaway System is a so-called "one-round" system or "worst-holes"
system that compresses the spread of gross scores when converted to net
scores. It is not a reliable handicap system and produces a result such
that the player with the lowest gross score almost always becomes the
low net score winner. Most players with higher gross scores are given
net scores within a few strokes of the winner so that most players can
feel competitive.
By the Callaway System, a player's allowance is determined after each
round by deducting from his gross score for 18 holes the scores of the
worst individual holes during the first 16 holes. The table below shows
the number of "worst hole" scores he may deduct and the adjustment to
be made, based on his gross score.
SCORE DEDUCT -- -- 70 71 72 scratch - no adjustment 73 74 75 -- -- 1/2 worst hole and adjustment 76 77 78 79 80 1 worst hole and adjustment 81 82 83 84 85 1 1/2 worst holes and adjustment 86 87 88 89 90 2 worst holes and adjustment 91 92 93 94 95 2 1/2 worst holes and adjustment 96 97 98 99 100 3 worst holes and adjustment 101 102 103 104 105 3 1/2 worst holes and adjustment 106 107 108 109 110 4 worst holes and adjustment 111 112 113 114 115 4 1/2 worst holes and adjustment 116 117 118 119 120 5 worst holes and adjustment 121 122 123 124 125 5 1/2 worst holes and adjustment 126 127 128 129 130 6 worst holes and adjustment
-2 -1 0 +1 +2 Add or Deduct to Handicap
 
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