Hierarchical Rule‐Based Activity Duration Estimation

Activity durations are often estimated by modifying standard work productivities for specific site and job characteristics. Modifications are typically developed from engineering judgment and past experience. In this paper, an explicit hierarchical rule-based framework for making such modifications is investigated. By explicitly formulating estimation rules, the factors felt to influence work productivity can be identified and the accuracy of particular modification rules assessed. Alternative estimation methods such as statistical techniques and a hybrid rule-and-statistical framework are discussed. A prototype expert system for masonry construction duration estimation, MASON, is described and used to illustrate the rule-based estimation approach. Facilities in MASON for explanation and productivity improvement analysis are also described.