Credibility analysis of a general hierarchical model

The hierarchical credibility model considered by Jewell (1975) is taken up. The hierarchy is extended, but it is shown that the credibility analysis of such a model can be reduced to a sequence of analyses of standard credibility models. A practical motivation of the more complex model is mentioned. It is illustrated that such a procedure does in fact yield the same results as the direct methods applied by Jewell to his hierarchical model. The estimation of second-order moments typically required by a credibility formula is considered and it is pointed out that no essentially new problems arise here either.