Construction baseline productivity: theory and practice

In this paper, the theoretical basis for construction labor productivity measurement is presented. In particular, the theoretical basis for baseline productivity measurements is developed by examining a productivity database consisting of 23 projects involving masonry construction. An important hypothesis is presented showing that as the design becomes more complex, the baseline productivity worsens. It is also hypothesized that higher values of the coefficient of variation indicates a higher variability in management and craft skills and in the use of technology. Two measures are proposed to measure the performance of individual projects: The disruption index and the project management index. These two measures identify the best and worst performing projects. Cumulative probability distributions of the disruption index and the project management index were also developed to evaluate the 23-project database and compare it with other databases. The hypotheses developed from the 23-masonry project database were tested against an 8-project database of concrete formwork and a 12-project database of structural steel erection. Strong support for each hypothesis was found using the two additional databases.