5. Conclusions and Further Research
In the original Data Envelopment Analysis (DEA) model that is used to measure the relative efficiencies of peer decision-making units (DMUs), it is assumed that in a multiple input, multiple output setting, all members of the input bundle affect the entire output bundle. There are many situations in real world, however, where this assumption does not hold, and where partial input to output interactions occur. Earlier work by Beasley (1995), Molinero (1996), Zu et al. (2013), Cook et al. (2013) and Imanirad et al. (2013) examined various aspects of the partial input/output problem, which was later extended in Li et al. (2015) to include multiple processes. The application used to develop the ideas in Cook et al. (2013) and Imanirad et al. (2013) involved measuring efficiencies of a set of steel fabrication plants.