Credibility for Experience Rating, A Minimum Variance Approach

This paper attempts to provide a relatively simple, but still mathematically meaningful context for applying Bühlmann credibility to large account experience rating. It further extends this to rating excess layers. It also allows for the inclusion of an additional complement of credibility to the traditional weighting of excess experience and ILF derived indications. Finally this paper gives guidance as to when exposure rating indications should not be used.