  We study how the quality dimension affects the social optimum in a model of
spatial differentiation where two facilities provide a public service. If
quality enters linearly in the individuals' utility function, a symmetric
configuration, in which both facilities have the same quality and serve groups
of individuals of the same size, does not maximize the social welfare. This is
a surprising result as all individuals are symmetrically identical having the
same quality valuation. We also show that a symmetric configuration of
facilities may maximize the social welfare if the individuals' marginal utility
of quality is decreasing.
