Abstract—Although the scale size of disputes in construction projects mainly follows the claim amount disputed, going through arbitration is considered as a one scale from the client point of view. So, study of foreseen risks for current and future situations is worthwhile to move in effective claim. Actually, due to the multivariate nature of construction contracts, things never go as planned. Thus, humans have developed many methods to resolve disputes, and arbitration is one of them. The study focused on modeling disputes occurring in construction industry field especially in Gaza Strip. Mathematical model, Regret Model for Arbitration (RMFA), has been built as a Decision Support System (DSS) which will recommend the user (contractor) whether to proceed to arbitration or not. The developed model depends on Regret Approach mainly and two logical and mathematical methods; Net Present Value (NPV) and Multi Criteria Analysis (MCA) to obtain more accuracy. This required to survey thirty questionnaires of respondents and some interviews with arbitration experts for identifying the influential evaluation criteria that need to be input into the model. After statistical analysis process using Statistical Package for the Social Sciences (SPSS) for these evaluation criteria which have been selected and weighed in order to measure their relative importance and impacts for the three probability values (Pe, Pf and Po) winning, current loses and future losses probabilities respectively which will be determined automatically by the RMFA, the weight values range of the selected ten evaluation criteria was (3.62 – 5). The Contract criterion is the highest and the Time and BoQ criteria are the lowest. Results of the model were tested in comparison with actual four disputes cases and the efficiency of the model achieved 75%.