In a recent paper, Karadima and Louri use frontier-based measures of market power and bank competition in an application to Euro Area banking. The purpose of the present note is to access their paper in a critical way, as there are certain fallacies and errors.

We use the concept of coarsened posteriors to provide robust Bayesian inference via coarsening in order to robustify posteriors arising from stochastic frontier models. These posteriors arise from tempered versions of the likelihood when at most a pre-specified amount of data is used, and are...