You are bound to run into cases in which a resource is available to you for only some portion of the time your project will be running. Suppose that your project begins on August 1 and a particular resource won’t become available to you until September 1. To account for the resource’s availability, use the Resource Information dialog box.

On the Resource Sheet view (on the View menu, click Resource Sheet), double-click the resource to display the Resource Information dialog box (see 3-5). Use the Resource Availability table on the General tab to set dates that describe when the resource will be available. You can set both starting and ending dates or set just a starting date. And if the resource will be available to you only part-time, use the Units column to specific a percentage less than 100 percent.

Figure 3-5. Use the Resource Availability table to identify the dates a resource is available.

You use a resource’s calendar to set exceptions to working time for a particular resource. Don’t get crazy here; if a resource is taking a half day off once for a doctor’s appointment, you really don’t need to set the exception on the resource’s calendar; in all likelihood, the resource will make up the time over the life of the project.

But if a resource has a two-week vacation planned in the middle of your project, you should set up that exception on the resource’s calendar to avoid assigning work to that resource during that period. Or if a resource’s work week doesn’t match the calendar assigned to the project—suppose that the resource works a 32-hour week, Monday through Thursday—you should set up all Fridays as non-working days on the resource’s calendar.

To set up an exception to a resource’s calendar, follow these steps:

Setting Up a Work Week Exception

To set up a work week exception for a resource who, for example, doesn’t work on Fridays, use the Work Weeks tab. Type a name for the exception such as "Off Fridays," set starting and ending dates, and then click the Details button. Project displays the Details For dialog box.

Select the Set Days To Nonworking Time option and click OK. When Project redisplays the Change Working Time dialog box, all of the days you specified between the beginning and ending dates appear underlined on the calendar; all Fridays appear shaded darker than Mondays through Thursdays.

Once you establish a resource’s availability, you can take advantage of your work while you assign resources. Earlier in this chapter, I showed you the basics for assigning resources. But now that you’ve factored in resource availability, let’s see how you can use the availability information while making assignments to avoid assigning an unavailable resource.

Let’s examine a simple case—you’ve got Tasks 1, 2, and 3 in your project, which begins on August 1, and you’ve got Resources 1 and 2 set up in the project. While working in the Gantt Chart view (on the View menu, click Gantt Chart), you select Task 1 and then click the Assign Resources button to display the Assign Resources window. Initially, both resources appear in the window (see 3-6).

Figure 3-6. Click the Resource List Options plus sign (+) to hide and display options you can use to filter available resources.

You can check availability before you make an assignment if you click the Resource List Options plus sign (+). Then select Available To Work and specify the number of hours per day a resource needs to be available for the task you selected. Project hides any resources not available to work in the timeframe of Task 1 based on examining their availability and their resource calendars and comparing that information to the duration of the selected task (see 3-7).

Figure 3-7. Filter for resources available to work the 10-day duration of the task.

In this example, when you filter for resources available to work 80 hours—the 10 days the task is scheduled to last—Project shows you that neither resource is available. In this example, Resource 1 is scheduled for a two-week vacation running from August 11 to 22, and Resource 2 doesn’t become available to work on the project until September 1. However, in the real world, I won’t be around to tell you why resources are not available. But you don’t need me; you can find out why these resources aren’t available for yourself.

To see what’s going on with your two resources, you can use the Graphs button in the Assign Resources window. First, clear your Available To Work filter so that you can see your resources; then click a resource and click the Graphs button.

Tip

You can display the graphs described below for more than one resource at a time. Press and hold the Ctrl key as you click each resource you want to graph. Then click the Graphs button.

Three graphs, which relate to the resource you selected and not to the task for which you’re considering assignment, are available in the Graphs window that appears:

Because the Assignment Work graph shows you what’s going on with the resource’s workload on both the selected task and other tasks, you often can spot an overallocation situation before it happens. In this example, Resource 1 isn’t assigned to any tasks beginning August 11, but Resource 1 also is not available. That information tells you that something is going on with the resource’s availability or calendar, and helps you avoid making an assignment that can’t be completed by this resource.

Sometimes you can avoid overallocating a resource. Assign overtime sparingly for two reasons:

While you might think that you can simply replace a burned-out employee who quits, people are actually your most costly resource. You invest money to train them and get them up to speed on the way your company operates, so replacing an employee costs your company money. So don’t make assigning overtime a regular practice—make it the exception to the rule.