ABSTRACT
Control has always formed the end purpose for systems of planning and scheduling construction work. Kelley and Walker (1959) stated that the plan should form the basis for management by exception: management need only act when deviations from the plan occur. This acceptance of this purpose for planning and scheduling systems, whether it be CPM with its intention to provide a method for “those responsible for a job when to start worrying about a slippage and to report this fact to those responsible for the progress of the project” (Kelley and Walker, 1959), or PERT with its expressed purpose to review work programs to assess the likelihood of achieving targets.
