A maximum-entropy approach to the linear credibility formula

Payandeh [Payandeh Najafabadi, A.T., 2010. A new approach to credibility formula. Insurance: Mathematics and Economy 46, 334–338] introduced a new technique to approximate a Bayes’ estimator with the exact credibility’s form. This article employs a well known and powerful maximum-entropy method (MEM) to extend results of Payandeh Najafabadi (2010) to a class of linear credibility, whenever claim sizes have been distributed according to the logconcave distributions. Namely, (i) it employs the maximum-entropy method to approximate an appropriate Bayes’ estimator (with respect to either the square-error or the Linex loss functions and general increasing and bounded prior distribution) by a linear combination of claim sizes; (ii) it establishes that such an approximation coincides with the exact credibility formula whenever the require conditions for the exact credibility (see below) are held. Some properties of such an approximation are discussed. Application to crop insurance has been given.