Page 224 - DCAP304_DCAP515_SOFTWARE_PROJECT_MANAGEMENT

Software Project Management

Notes Figure 11.4: Resource Demand Compared to Resource Availability

We will begin by analyzing the issues involved in resource leveling for a situation where a bar
chart has been used as the primary planning technique for a simple project. The reason for this
is that resource leveling must be considered within a time framework and bar charts are drawn
to a time scale while networks are not. Examine Figure 11.2 in this figure, the time-scale for the
activities comprising the project are shown in a bar chart, which also shows resource requirements
for one particular resource unit. An examination of the bar chart and its associated resource chart
in Figure 11.2 shows that improvements can be made to the level of resource requirements by:

 Delaying or bringing forward the start of certain activities.
 Extending the duration of certain activities and so reducing the demand for resources over
the duration of the activity or by a combination of both of these adjustments.
However, there are problems with using the simple bar chart as a tool for resource leveling. For
example, we do not have any information about the interdependency of tasks. Therefore, if we
delay a task by starting later than originally planned or by extending the duration of the task, we
cannot evaluate the exact impact this will have on the overall project. Referring to Figure 11.2
again, if we assume that the maximum amount of resource availability is 14 units, then we have a
problem in week 2 because 18 units of resources are required in that week. In order to reduce the
resource demand in week 2, we may have to extend Activity A into week 3 (if this is possible) and
spread the resource demand over three weeks, or delay the commencement of Activity B. However,
the exact impact of these changes on the overall project duration cannot be easily determined.
Another issue is that the critical path(s) cannot be easily determined, although we may be able to
deduce which activities are critical by inspection. Clearly, if we do not wish to extend the overall
duration of the project we must avoid extending or delaying activities which are on the critical path.

Notes Finally, the availability of slack or float is not clear. Knowing this is important
because it is this attribute that can be utilized to adjust our resource requirements.

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