Effects of Delay Times on Production Rates in Construction

Factors that can be fairly easily identified and modified and can lead to significant improvements in production rates for activities in construction are considered in this paper. These factors are divided into four work categories. Two of the four work categories in which each construction activity was subdivided were idle and waiting times. Productivity measurements generally do not distinguish between the idle and waiting times. Conclusions can therefore be misleading, and more importantly, the attention of management is only vaguely and imprecisely directed to the cause of the inefficiencies. The breakdown of nonproductive time into two factors is therefore very important in directing the attention of management to the root causes of inefficient time. The variation in production rates used by contractors' estimators are given and compared with actual on-site production rates. The frequency of different sources of information used by contractors when estimating production rates, and the percentage use of production monitoring methods, are also given. A prototype expert system, using the Personal Consultant Plus shell program of 1987, was developed to assist in the acquisition and management of knowledge and data for the estimation of production rates.