To describe operations, several variables have been considered. There are a lot of metrics that can describe the activities of a LSP. Krauth et al. (2005) propose a list of 130 elements classified by the perspectives of different stakeholders.
Among those, relevance is assumed by the kilometers per day, the labor utilization, the number of deliveries and the delivery
performance. Lin et al. (2010) suggest to take into account the vehicles’ capacity and Gunasekaran et al. (2001)
highlight the importance of the number of faultless deliveries. The company under study monitors a lot of elements
related to its business, and several of these, that are supposed to influence the level of productivity have been
included into the model. In particular: