Simulation and experimental design applied to sizing supermarket cashiers in Colombia

A framework for Colombian supermarkets challenges in order to find an adequate number of cashiers and baggers was developed, translated to a simulation model using Promodel® and proved through an experiment varying register item time, number of cashiers and number of baggers for eight real Colombian supermarkets. The framework proved to be successful in finding a cashier-bagger combination for average waiting and system times, but not powerful enough for service promises involving all of the most part of the clients due to variability of maximum times. An interaction among cashiers and baggers combination was found that makes valuable to increase the number of baggers only for some specific number of cashiers working.