Adding Qualitative Context Factors to Analogy Estimating of Construction Projects

Existing estimating models have certain shortcomings in the management of historical data. There is a need of defining more objective and consistent criteria for the selection of historical construction data to be used for estimating. In this perspective, a methodology based on historical information, which incorporates qualitative context factors to the structure and use of this information for cost estimating, such as project complexity, environmental conditions and characteristics of workmanship, among others, is proposed. A list of qualitative project context factors that are most influential for construction projects’ cost and productivity is presented. Additionally, a context model that includes these variables is described together with an explanation of how they are incorporated into the cost estimate. It is concluded that the incorporation of qualitative context factors in cost estimating improves the use of historical information and that most critical aspects to achieve this feature are the creation of a reliable site-work feedback system and the correct structure of historical information.