The Critical Path Method (CPM) - Construction Project Scheduling and Control - page 55

error terminates the calculations in any CPM computer program. This author
strongly recommends that when drawing (or inputting) the relationships, you
do so from one side only. This means looking at either predecessors or suc-
cessors, not both at the same time. This author personally prefers dealing with
predecessors. When reviewing the logic, you can look at both ends of an activity
to determine the accuracy of the logic.
6. Implement the schedule
Implementing the schedule means taking the scheduling from paper to execution.
This step is important for fulfillment of the schedule. Most importantly, the scheduler
(under directions from the project manager) must choose start and finish dates within
the range of the calculated dates (early and late). When an activity has a range of dates
(e.g., can start as early as 13 June 2011 and as late as 11 July 2011), it is not a good
idea to give the choice of date selection to the field crew or even to the subcontrac-
tor. Computer software programs choose the early dates by default, unless there is a
constraint forcing other dates.
Every participating party must receive correct information at the appropriate time.
Too little or too much information may be counterproductive. Four important points
should be noted: First, the schedule must be realistic, fairly accurate, and accepted by
all parties. Second, the upper managers must take it seriously. Third, communication
channels must remain open and clear among all project participants throughout the
project duration. All parties must be informed of any change that may occur to the
schedule. Fourth, such implementation and commitment must continue throughout
the project.
7. Monitor and control the schedule
As defined in Chapter 1, project control means comparing the baseline (what was
planned or what was supposed to have been done) with what actually has been done,
analyzing any deviation (variance) from the baseline, and taking corrective action
whenever and wherever needed. The main difference between the two terms ( moni-
tor and control ) is in the corrective action taken. Monitoring includes observing and
reporting, and perhaps analyzing. Control adds corrective action to this definition.
The schedule may be monitored by the owner or the project management consul-
tant (PMC). These two parties have no power to take direct corrective action during
execution of the project. Only the party who is executing the work (usually the GC
and subcontractors) can take direct corrective action. As in the last step, keeping open
communication channels among all involved parties and disseminating appropriate
and timely information are extremely important.
An important part of the control effort is forecasting Forecasting is done mostly by
extrapolating the actual performance for the remaining portion of the project. When
actual performance is below the baseline, forecasting is used more as a warning. For
example, the project manager may say, “We are 20% complete for the project and
we are $10,000 over budget. If we don't make an adjustment, we'll finish the project