  An important problem in precision cosmology is the determination of the
effects of averaging and backreaction on observational predictions,
particularly in view of the wealth of new observational data and improved
statistical techniques. In this paper, we discuss the observational viability
of a class of averaged cosmologies which consist of a simple parametrized
phenomenological two-scale backreaction model with decoupled spatial curvature
parameters. We perform a Bayesian model selection analysis and find that this
class of averaged phenomenological cosmological models is favored with respect
to the standard $\Lambda$CDM cosmological scenario when a joint analysis of
current SNe Ia and BAO data is performed. In particular, the analysis provides
observational evidence for non-trivial spatial curvature.
