  Models of the Universe like the Concordance Model today used to interpret
cosmological observations give expectation values for many cosmological
observable so accurate that frequently peoples speak of Precision Cosmology.
The quoted accuracies however do not include the effects of priors used in
optimizing the Model nor allow to evaluate the confidence one can attach to the
Model. We suggest an estimator of the Confidence Level for Models and the
accuracies of the expectation values of the Model observables
