Constraining the evolution of red supergiants with the integrated light of star clusters

The integrated properties of young star clusters are subject to large cluster-to-cluster variations because they depend directly on small numbers of bright stars. At ages at which red supergiants are expected to exist, these luminous but rare stars can be blamed for most of the variations. If unresolved clusters are to be used to constrain red supergiant models, methods must be developed that take these stochastic fluctuations into account. We discuss prospects and open issues in this field, based on recent work on high mass clusters in M82, and on first experiments towards a Bayesian study of cluster populations.