This paper provides an overview on classical and new methods for testing time series properties of migration matrices. It is well known that due to cyclical behaviour of the economy transition matrices for many credit portfolios cannot be considered to be constant through time. Further,...

In this paper, we show the importance of accounting for heterogeneity among sample firms in stochastic frontier analysis. For a fairly homogenous sample of German savings and cooperative banks, we analyze how alternative theoretical assumptions regarding the nature of heterogeneity can be...