“…In addition, cross-training in a single department or between departments can be considered (Van den Bergh, 2013), the possibility of overtime can be included (Wright & Mahar, 2013) and, for each worker, primary and secondary skills can be distinguished (de Matta & Peters, 2009;Guerry et al, 2013). In this paper, several straightforward assumptions regarding these options have been adopted: categorical skills, homogeneity of workers regarding learning, one single department, with no overtime considered.…”