Filippini, Massimo Koller, Martin 2012 The purpose of this study is to analyze the level of cost efficiency of Swiss Post’s postal delivery units to enable policy makers’ as well as Swiss Post to decide on the reactions to market changes. In particular, we use different panel data models to assess cost efficiency in these units to account for unobserved heterogeneity. The results from applying Mundlak’s formulation to the Pooled stochastic frontier model provides evidence that this model is not affected by a heterogeneity bias and that the cost efficiency values lie within a lower and upper bound of the other recent and standard econometric frontier models. Overall, the analysis shows that assumptions on unobserved heterogeneity are crucial and that results of econometric cost efficiency measurement models have to be interpreted with corresponding caution application/pdf https://n2t.net/ark:/12658/srd1318500 https://susi.usi.ch/global/documents/318500 https://susi.usi.ch/documents/318500/files/wp1206.pdf eng info:eu-repo/semantics/altIdentifier/ark/12658/srd1318500 info:eu-repo/semantics/openAccess License undefined Cost efficiency stochastic frontier model unobserved heterogeneity Mundlak postal delivery network info:eu-repo/classification/udc/33 Cost efficiency measurement in postal delivery networks http://purl.org/coar/resource_type/c_816b