The ranking-aggregation problem in manufacturing: potential, pitfalls, and good practices

A number of experts, who individually rank a set of objects based on a certain attribute, and the need to aggregate the resulting (subjective) rankings into a collective judgement: these are the “ingredients” of the ranking-aggregation problem, which is typical of social choice, psychometrics and economics. This paper shows that the problem has many interesting applications even in manufacturing and must be approached with care, in order to avoid misleading results. Through a real-world case study concerning cobot-assisted manual (dis)assembly, the paper illustrates (i) a methodology to tackle the problem in a practical and effective way and (ii) various useful tools (e.g., for estimating the degree of concordance among experts, the consistency and robustness of collective judgment, etc.). The article is addressed to scientists and practitioners in the manufacturing field.