Manage Your Projects Using the “Nearly” Critical Path

Many project managers like to manage their projects by focusing on the Critical Path. Remember that the Critical Path consists of all tasks with a Total Slack value of 0 days. All tasks on the Critical Path are known as Critical tasks, and cannot slip without impacting the final Finish date of the entire project. I like to describe Critical tasks as the tasks that have no “wiggle room” or “no room for things to go wrong.” If a Critical task slips, then the Finish date of the entire project slips as well. For example, if a Critical task slips by 5 days, then the Finish date of the entire project is now 5 days late as well.

Managing a project by the Critical Path is a good thing, as it allows you to focus your efforts on the tasks that have the most impact the final Finish date of the project. However, have you ever had a non-Critical task slip, and then your project Finish date slipped as well? If so, then it would be good for you to know how to display the “Nearly” Critical Path in your project.

Before I describe how to see the “Nearly Critical Path”, let me remind you how to see the true Critical Path. In either Microsoft Project 2010 or 2013, complete the following steps to display the Critical Path:

1. Display the regular Gantt Chart view.
2. Click the Format tab to display the Format ribbon.
3. In the Bar Styles section of the Format ribbon, select the Critical Tasks checkbox as shown in Figure 1.

Figure 1: Select the Critical Tasks checkbox

Microsoft Project indicates the Critical Path by displaying red Gantt bars for Critical tasks and blue Gantt bars for non-Critical tasks, as shown in Figure 2. Notice that the Critical Path begins with task ID #5, the Perform Server Stress Test task. The Critical Path also includes all of the tasks in the TESTING phase of the project and the last few tasks in the TRAINING phase of the project.

Figure 2: Critical Path displayed with red Gantt bars

A key question to ask at this point is, “Why are the first three tasks non-Critical tasks instead of being Critical tasks?” To answer this question, we need to apply the Schedule table by completing the following steps:

1. Click the View tab to display the View ribbon.
2. In the Data section of the View ribbon, click the Table pick list button and select the Schedule table, as shown in Figure 3.

Figure 3: Apply the Schedule table

3. Drag the split bar to the right edge of the screen so that you can see the Total Slack column.

The Total Slack column tells you how many days late a task can finish without impacting the Finish date of the entire project. Notice in Figure 4 that the first three tasks have 2 days of Total Slack each. This means these tasks can slip a total of 2 days without impacting the final Finish date of the project. If any of these tasks slips a total of 3 or more days, then the final Finish date of the project will slip as well. In other words, sometimes a non-Critical task slips, and the final Finish date of the project slips as well.

Figure 4: Schedule table shows tasks with slack

The “Nearly” Critical Path is the series of tasks that have a Total Slack value greater than 0 days, but are “nearly” on the Critical Path. In your own projects, the “nearly” Critical tasks might have 1 or 2 days of Total Slack, or they might even have 10 or more days of Total Slack in a large, long-duration project. In my case, I would like the Critical Path to include “nearly” Critical tasks that have 2 days or less of Total Slack. This way, I will be able to see the true Critical Path, along with the “Nearly” Critical Path as well. To display the “Nearly” Critical Path, complete the following steps:

1. Click the File tab and then click the Options button in the Backstage. Microsoft Project displays the Project Options dialog.
2. In the Project Options dialog, click the Advanced tab and then scroll down to the bottom of the dialog.

In the Calculation options for this project section of the dialog, notice the last option at the bottom of the dialog, which is the Tasks are critical if slack is less than or equal to _____ days option shown in Figure 5. This is the option you use to display the “Nearly” Critical Path, along with the true Critical Path. If you want to see “nearly” Critical tasks that have 2 days of Total Slack, change this option to 2 days. If you want to see “nearly” Critical tasks that have 10 days of Total Slack, change this option to 10 days.

Figure 5: Project Options dialog, Advanced page

3. In the Calculation options for this project section of the dialog, specify a value greater than 0 days in the Tasks are critical if slack is less than or equal to _____ days option.
4. Click the OK button.

In my project, I want to include tasks with up to 2 days of Total Slack in the Critical Path, so I changed the Tasks are critical if slack is less than or equal to _____ days option to 2 days. Figure 6 shows the Gantt Chart after changing this option. Notice that the first three tasks now have red Gantt bars instead of the blue Gantt bars they had previously.

Figure 6: “Nearly” Critical Path displayed in the Gantt Chart

At this point, you are probably saying to yourself, “OK, great. I can now see the true Critical Path (tasks with 0 days of Total Slack) and the ‘Nearly’ Critical Path (tasks with Total Slack of up to 2 days), but how can I tell the difference?” There are several methods you can use to determine which tasks are truly Critical and which tasks are “nearly” Critical.

The first method is to right-click on the Task Name column header, to select the Insert Column item on the shortcut menu, and to select the Total Slack column. Doing this will temporarily insert the Total Slack column to the right of the Task Name column. In the Total Slack column header, click the AutoFilter pick list arrow button and select a value. If you want to see only true Critical tasks, select only the 0 days value. If you want to see the “nearly” Critical tasks, select the value you specified in the Project Options dialog. For example, Figure 7 shows the project when I AutoFilter for tasks with 2 days of Total Slack to see the “nearly” Critical tasks.

Figure 7: Nearly Critical tasks

The second method is to create a custom filter that displays “nearly” Critical tasks and then apply the new filter as a Highlight filter. To create the filter, click the View tab to display the View ribbon. In the Data section of the View ribbon, click the Filter pick list and select the New Filter item. In the Filter Definition dialog, set up your filter criteria similar to those shown in Figure 8 and then click the Save button.

Figure 8: Filter Definition dialog

To apply the new custom filter as a Highlight filter, click the Highlight pick list in the Data section of the View ribbon, and then select your new custom filter. For example, Figure 9 shows my project with the new _Nearly Critical Tasks filter applied, highlighting in yellow all tasks that are “nearly” Critical tasks. This helps me to easily distinguish between “nearly” Critical task and true Critical tasks.

Figure 9: Nearly Critical tasks highlighted in yellow

A version of this article originally appeared on the Sensei Project Solutions blog.