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REVIEW OF BASIC RESOURCE SCHEDULING 151

For the short term, look at unleveled and leveled solutions. If the leveled solu-
tion has a good utilization factor (not too many peaks and valleys), you may wish
to use the computer-produced schedule, as-is. If not, use the computer data to
determine a reasonable resource pool (if adjustable) or a reasonable task load (if
resources are fixed), and determine an optimum short-term schedule (i.e., next
two weeks), using the computer to display the results of the various what-ifs.

Tool Tip Software that allows you to preview a result before
accepting, or that has an undo feature, can be helpful in this
optimization exercise.

Warning: Use of Total and Free Float Disallowed We use total float as an indica-
tor of the time that a task may slip without delaying the shortest completion of the
project. We use free float as an indicator of the time that a task may slip without
affecting the start of any other task in the project. When we use resource leveling,
we can forget about using the resultant float values as a time management tool.

The system may use float in determining the priorities for scarce resources. So
it is important to develop a sound schedule, which contains valid float values. But,
once we execute the leveling process, we can no longer assume that sliding out
the work while staying within the float is not going to hurt the ability to get the
work done on time, because we need to consider the effect on resource availabil-
ity. This being the case, it should serve to further justify a short-term philosophy.

Trap Once you have adopted a resource-leveled schedule,
the indicated schedule floats are no longer useful as a mea-
sure of allowed schedule slippage. Any deviation to the
planned performance of a task, even those having float or
even those not requiring resources (except non-resource tasks
having free float), will cause a change in the resource loads.

A Review of Basic Resource Scheduling Practices

Project Model The first step of the resource scheduling process is to build a
sound model of the project work that is to be performed. We highly recommend
the use of critical path based software to aid in this task. This initial plan should