  We discuss the role of cumulants of net baryon number fluctuations in the
analysis of critical behavior in QCD and the study of freeze-out conditions in
heavy ion experiments. Through the comparison of the current set of
measurements of higher order cumulants of net baryon number fluctuations with
lattice QCD calculations and results from hadron resonance gas model we can
learn to what extent freeze-out as, determined by such cumulants, occurs close
to the QCD transition temperature and thus can probe critical behavior at small
values of the baryon chemical potential. Understanding how the relation between
freeze-out conditions and the QCD crossover transition is reflected in
properties of the experimentally determined cumulants is an important
prerequisite to search for the QCD critical point. We point out that even if
perfect continuum extrapolated lattice QCD results would be available, it would
be inappropriate to use these observables to extract the value of the QCD
transition temperature at vanishing baryon chemical potential from experimental
data. We furthermore provide indications that a recently performed comparison
of lattice QCD results on cumulants with data from heavy ion experiments suffer
from systematic as well as statistical uncertainties in the lattice QCD
calculations. This makes such comparison of lattice QCD calculations with
experimental data at present not useful.
