Specialists’ knowledge and cognitive stress in making pairwise comparisons

There is no lack of studies dealing with the consistency of evaluations performed by pairwise comparison in the decision-making literature. Mostly, these studies offer algorithms for reducing the inconsistency of evaluations and indices to measure the evaluation’s consistency degree. The focus on these two research fronts does not cover all the gaps associated with the inconsistent evaluation problem. The existing algorithms are difficult to implement and do not preserve the original evaluations since the original evaluation matrix is replaced with a new matrix. Furthermore, the inconsistency of pairwise comparison has been associated with the specialist’s bounded rationality only at the theoretical-conceptual level. This research investigates the relationship between the lack of specialist knowledge and the inconsistency of evaluations, as well as introduces an approach that ensures the evaluation’s consistency by reducing the specialist’s cognitive stress when comparing a high number of alternatives. The results reveal that the specialist’s limited knowledge about the topic does not impact the degree of consistency of the evaluations as expected. The evaluation’s consistency degree is 59% lower when the specialist does have no knowledge about the decision topic but has theoretical knowledge and experience in evaluating alternatives by pairwise comparison. This is a remarkable contribution with a high degree of universality and applicability because instructing decision-makers on the inconsistency problem is a cheaper, easier way to increase the evaluation’s consistency degree without altering the original information. Furthermore, the introduced approach reduces the number of evaluations and evaluation time by 8.0 and 7.8 times, respectively.