  This paper exhibits a duality between the theory of Revealed Preference of
Afriat and the housing allocation problem of Shapley and Scarf. In particular,
it is shown that Afriat's theorem can be interpreted as a second welfare
theorem in the housing problem. Using this duality, the revealed preference
problem is connected to an optimal assignment problem, and a geometrical
characterization of the rationalizability of experiment data is given. This
allows in turn to give new indices of rationalizability of the data, and to
define weaker notions of rationalizability, in the spirit of Afriat's
efficiency index.
