When observers judge the amount of a reward they consider just for tar
get recipients, they may treat male and female recipients, differently
, and this gender-based double standard my itself differ by the observ
er's own gender. In this paper we develop a framework that enables qua
ntitative assessment of multiple standards as well as of the mechanism
s by which they operate. The framework also makes it possible to test
for differences in multiple standards across different subsets of resp
ondents; and it is applicable to questions of multiple standards in bo
th justice judgments and allocation decisions. To illustrate the frame
work, we examine a special case of multiple standards--gender-based do
uble standards--and we focus on judgments of just earnings, using data
collected by Rossi's factorial survey method. We conduct two main set
s of analyses, the first focusing on the double standard and the secon
d on the mechanisms by which the double standard operates. In the firs
t set we estimate the just gender wage gap, in the eyes of male and fe
male observers separately, establishing the existence and direction of
the just gender wage gap and quantifying the differential across male
and female observers. In the second set we assess the mechanisms by w
hich the double standards operate, separating and quantifying two mech
anisms--double standards in the just base wage (i.e., the base wage re
garded as just by the observer) and in the just rate of return to scho
oling (i.e., the rate of return to schooling regarded by the observer)
--establishing their direction and testing whether the mechanisms diff
er by observer's gender.