Resumen
Studies show that procurement management and its processes strongly affect project success in the construction industry, because the project-oriented organizations in the construction industry prefer to buy goods and services from outside the project team and benefit from outsourcing. Hence, these organizations are continually facing different levels of procurement processes, and the establishment of a robust outsourcing system is crucial for success of their projects and development of their businesses. On the other hand, the housing projects are considered a significant sector of the construction industry in terms of the number of projects and the impact on the national economy. Traditionally, the key sources in conventional housing projects are the general contractors, the consultants and the suppliers. In this study, essential elements of an organizational system have been investigated by expert opinions and through the Delphi method, and all effective aspects of the source selection problem have been identified and integrated. Based on the research findings, procurement of housing construction projects should be organized in three organizational levels: development of the long list, preparation of the short list and selection of the most appropriate source by focusing on four main elements of the source identification method, criteria definition, evaluation arrangement and assessment model.