A fuzzy method for the selection of customized equipment suppliers in the public sector

Abstract

The acquisition of customized equipment usually requires the selection of a technology supplier to accomplish a developmentproject. This requires the evaluation of the suppliers’ proposals that may be assessed by different evaluators in different ways(single numerical values, intervals or linguistic values). In the public sector, this process may require the prior publication ofthe scoring rules in a request for proposal (RFP). This may force the evaluators to assign weights in advance to characteristicswhose technical significance is known but whose significance for the evaluation is unknown. An inappropriate assignation ofweights in the evaluation may lead to wrong conclusions. The objectives of the research were the implementation of a methodfor the evaluation of offers, including the adaption of weights as part of the evaluation process without violating the principles oftransparency and non-discrimination that are generally required by the legislation; the integration of quantitative and qualitativecriteria in a flexible procedure; and the verification for possible rank reversals. This paper proposes the use of trapezoidal fuzzynumbers (TFN) for the simultaneous implementation of different types of evaluations, incorporates variable weights analysis(VWA) for the subsequent adjustment of weights, and proposes a simple method for the detection of rank reversal. A numericalexample is presented using data from an actual case.