ranking constant c a model for the distribution of specific values of varying discriminatory power involves a r. c.; fR = f0 e–cR where f is the frequency of a particular value (R = rank, 0 = highest rank), e is the base of natural logarithms and c the r. c.; knowing the number of different values (greatest R) and the lowest frequency (usually 1), and the frequency of the highest ranked value, we may solve for c, i.e, the r. c. for the field, cf. reversed J-shaped, decay curve, value specific, value specificity constant).