On Comparisons of Sensitivity, Specificity and Predictive Value of a Number of Diagnostic Procedures

Specificity (Q), senisitivity (Xq) and predictive value (p) have been proposed as measuies of the effectiveness of each of say t diagnostic procedures in the detection of a disease D (e.g., Thorner and Remein 1961; Vecchio, 1966). It is assumed that a definitive result can be obtained on the presence or absence of D in each of a series of n patients together with their diagnoses by the t procedures. In this paper x2 tests are developed for homogeneity of 7, 7, and p. These utilize matched sample x2 results of the author (Bennett 1967; 1968).