RT Journal A1 BOBA A T1 UNderlying flaws in the sarnoff curve JF Archives of Surgery JO Archives of Surgery YR 1979 FD September 1 VO 114 IS 9 SP 1092 OP 1093 DO 10.1001/archsurg.1979.01370330114030 UL http://dx.doi.org/10.1001/archsurg.1979.01370330114030 AB To the Editor.—Careful analysis of Dr Del Guercio's comments about the article by Samii et al that appeared in the Archives (113:1414-1416, 1978) shows a serious conceptual flaw in the logic underlying the "Sarnoff diagram." To find the flaw, one must look to the "dimensional" aspects of the x and y axes and to the quantities that are plotted on them. One should really think in terms of a "mapping" process, where individual members of one set (values for pulmonary wedge pressure) are placed in some certain correspondence with individual members of another set (the positive integers) in such a manner that certain relationships that exist between objects of the sets are retained after the mapping operation is completed; in this case, a wedge pressure of 9 is higher than a wedge pressure of 8, just as the cardinality of the number 9 is greater than the cardinality of