Assigning a Different Resource
Suppose a resource works on two simultaneous tasks on the critical
path. You can’t delay either one without affecting the project finish
date. In this situation, the Assign Resources dialog box (choose Resource→Assignments→Assign Resources) can help you find someone with similar skills
who has more time available. If money is a bigger problem than time,
you can replace the person with someone who costs less (assuming that
the replacement can get the work done in the same amount of time).
If you use a custom field like an outline code to identify
resources’ skills, in the Assign Resources dialog box, turn on the
“Filter by” checkbox. Apply a filter to show resources with similar
skills, like the Group filter or a custom filter that looks for job
description codes. Then, turn on the “Available to work” checkbox, and
then type the number of work hours you want from the new resource
during the task duration. If the resource you’re replacing is assigned
80 hours over 2 weeks, type 80h to look for someone who can work full time, as Figure 10
shows. When you use the “Filter by” features, the Resources table
displays the assigned resources, plus any others who have the available
time you specified.
Select the resource you want to replace, and then click Replace. In the Replace Resource dialog box, type a percentage in the replacement’s Units field, and then click OK.
Tip
The Assign Resources
dialog box doesn’t tell you how many hours the current resource is
assigned, which makes it difficult to fill in the “Available to work”
box. To see how many hours the current resource is assigned, display
the Task Form in the view’s bottom pane. (Choose View→Split Views, and
then, in the Details drop-down list, choose Task Form.) The Work cell
shows the number of hours the resource is assigned.
You can add resources to any task you want. The only special view that may help is the one that shows only the critical path . However, you must use judgment to decide whether more resources are going to help or hinder.
Using Slack Time to Shorten the Schedule
When a resource works on critical and noncritical tasks at the same
time, you can shorten the critical task’s duration by assigning more of
the resource’s time to it. By definition, the noncritical task has
slack time, which means you can delay its finish date without delaying
the project. Although the noncritical task takes longer, the increase
in duration merely consumes some of the task’s slack time, as you can
see in Figure 11.
To see slack
time in a Gantt Chart timescale, use the Detail Gantt view. Choose
View→Task Views, click the down arrow next to the view button, and then
choose Detail Gantt. Task slack time appears as narrow black bars on
the right end of task bars. The text at the right end of the slack bar
gives you the amount of free slack.
In Figure 11,
the critical “Build forms” task in the top window ends on June 7. The
“Assemble frame components” task in the top window has 6.5 days of
slack. The “Build forms” task in the bottom window uses more of the
person’s hours, so it ends earlier, on June 2. By moving some of the
person’s hours to “Build forms,” the slack time for “Assemble frame
components” drops to zero (which turns this task into a critical task).
This juggling of
hours was successful, because the critical “Frame-in shell” task went
from a start date of June 20 to starting on June 15, 5 days earlier,
reducing the critical path by 5 days.
