ABSTRACT
British golfers discovered long ago that harder courses magnify differences in ability and developed a system of handicap adjustment that recognized this but the system was discontinued somewhat later. In the 1970s, magnification was rediscovered by Soley (report to the USGA) and also in (Scheid, 1973) leading eventually to the USGA’s development of the slope system (Stroud and Riccio, 1990). The research involved in all these studies was based on data from the amateur side of scratch.
It has occasionally been suggested that the system is flawed on the other side of scratch, the “plus” side, that over there it is demagnification that must rule. This is not a thought that appeals to scientists, who prefer and search for general principles. The slope system has consistently respected the simple logic that it is the stronger player who is better prepared to cope with added difficulties, whether between scratch and bogey players or between touring pro and scratch. Until recently this has been an article of faith in simple logic and consistency of principle. The research now being reported was based entirely on scores from professional tours and suggests that this faith has been justified.
