A decision support system for the selection of the optimum contractor

Awarding the tender to the lowest bidder can result in potentially serious problems, which necessitate the need for including a wide range of other criteria. This will form the basis of selection, where some of these criteria will be contractor related and others will relate to the specific characteristics of the project and the requirements of the owner. This research develops a decision support system that combines the different characteristics of the contractors with the specific conditions, requirements and objectives of the project under consideration. This research was divided into six phases. Phase (1) literature review to identify and investigate all criteria related to the contractor selection by identifying the root causes of the problems resulting from selecting an inappropriate contractor. Phase (2) literature review to identify an efficient and scientific method for the criteria identification and assessment for the collected criteria. The Delphi method was found to be an efficient technique to identify the criteria regarding the contractor and the Analytic Hierarchy Process (AHP) an efficient method to assess the criteria for each project on a project-by-project basis. Phase (3) refinement and evaluation for the collected criteria by implementing the Delphi method using questionnaire and structured interviews to get the expert opinion. Three countries were surveyed namely: (i) Egypt, (ii) Kuwait and (iii) the UK. Phase (4) researches decision support system techniques to structure the proposed contractor selection decision system (DSS). ABP was also found an efficient method to be used in structuring the DSS. Phase (5) structuring the logic of the contractor selection decision system. The system is divided into two processes. The first one is the contractor screening and pre-qualification process and the second process is the final selection process. A combination of the criteria that were investigated by the Delphi method with those that were assessed by the ABP is carried out to produce a short list of contractors that continues in the next stage. This combination accumulates expertise of the contract award and considers the project individuality and hence provides the required flexibility, which is a key objective of this research. An extended enhanced Knowledge-Based Expert System was developed to enable the new DSS to be used as a practical management tool. Phase (6) verification and analysis of the contractor selection system developed. A simulated project case is used to illustrate the logic consistency, workability and flexibility. A sensitivity analysis is performed to verify the system using case studies. The analysis established that the DSS is not sensitive to a single criterion and can even tolerate the miss judgment in single criteria due to the fact that the use of multiple criteria.