This study aims to develop a mathematical model for evaluating the objective abilities needed for negotiation and to provide a tool that companies can use to select a negotiation team. The model was constructed using a Likert pentagonal scale, where numbers from 5 to 1 represented the level of agreement or disagreement, and seven objective abilities were considered, including analytical ability, economic knowledge, legal knowledge, linguistic ability, psychological understanding, normative understanding, and general knowledge. The model was tested using a structured interview (sixteen interviews) with experts and specialists in the construction industry as a case study and then validated by quantitative data analysis method using first-order confirmatory factor analysis (CFA) with a sample of consultants (220 responses) from companies and offices related to the construction sector. The study found that the model is valid for use in the construction industry and can be useful for selecting negotiators. The developed model can be used, adapted, and modified according to the needs of different negotiation situations. This research is the first of its kind to develop a mathematical model for evaluating negotiating abilities and can be used as a model for similar research studies.