To focus on the critical and near critical tasks, group your tasks based on the Total Slack field:

Insert the Total Slack field. Using the auto filter pulldown for Total Slack, select Group by, and then select Duration.

 
 
The detailed tasks will be grouped by the values in the Total Slack field. You can collapse and expand each section.

If the critical path Total Slack is positive, you will see the Target Complete milestone shown with 0 days Total Slack. This is because it has the MFO assigned.

Then all remaining tasks will be displayed in ascending Total Slack order.

The tasks with the smallest Total Slack appear at the top of the list. These tasks, excluding the Target Complete milestone, make up the critical path. In our example, the critical path has 8 days of Total Slack. You should focus on these, and any other tasks that don’t meet your Critical Task Threshold.

You may use the auto-filter pulldown to display only the tasks that don’t meet the Critical Task Threshold for your project by unchecking those that are greater than the threshold.

 
Typically, the tasks with the longest Durations are likely candidates for compression. If you need to compress your schedule to increase the slack in your critical path, you may sort the tasks within the groups, by using the auto-filter pulldown for the Duration field and choosing Sort Largest to Smallest. This will sort the longest tasks to the top of the list in the group.
Then starting with the longest tasks, analyze how they may be compressed using crashing or fast-tracking. Crashing and fast-tracking are described in more detail in Lesson 7 Project Monitoring and Control chapter 3. Impact Analysis and Corrective Action.

There are other options available to help you view critical and other path related information.

Task Inspector

The Task Inspector displays key schedule information for the currently selected task in an added pane to the left of the task table. It shows what is driving the task to Start on the date it is currently scheduled. The Task Inspector is dynamic, meaning when you select a different task, the information displayed is based on that new task’s drivers.

Some of the drivers it may list include:

  • Predecessor
  • Constraint
  • Actual Start
  • Calendar
  • Project Start Date

To display the Task Inspector, on the Task ribbon, in the Tasks section, select the Inspect button.

In this example, ID 28 is selected. This task has 2 predecessors (24 and 27 listed in the Predecessor column), but in the Task Inspector, it only lists ID 27. Task 27 is the predecessor with the driver because it has the latest early date.

In this example, the Task Inspector pane also lists the Standard calendar. ID 27, the predecessor, finishes on 8/2/23 at 5:00 PM. So theoretically, Task 28 should be able to start then. However, it is using the Standard calendar that is assigned to the Project, so it can’t start until the next day.

The Predecessor ID and Name in the Task Inspector pane is a hotlink. If you click on it, that ID will be selected and the driving information for that task is now displayed. You may continue to click on each Predecessor hotlink to trace back through any path. This may be used for the critical path or any near critical paths that you need to understand in more detail.

Task Path

The Task Path option provides visibility to preceding and succeeding tasks for a selected task. The highlighting is dynamic, meaning when you select a different task, the highlighting is based on that new task’s linking.

There are four toggles (on/off) that highlight predecessor and successor tasks in different colors. You may view:

  • Predecessors (yellow) – Any tasks that precede the selected task in a path.
  • Driving Predecessors (orange) – Tasks that precede the selected task in the path that drives the selected task to its current Start date.
  • Successors (light purple) – Any tasks that follow (succeed) the selected task in a path.
  • Driven Successors (dark purple) – Tasks that follow (succeed) the selected task in a path that is driven by the selected task to its current Start date.

To use the Task Path option, on the Format ribbon, in the Bar Styles section, click the Task Path pulldown, and click on one of the toggle options. They must be turned on one at a time. You may turn on one or multiple for viewing and analysis.

You may turn them off one at a time by clicking on the toggle, or all at once by selecting Remove Highlighting.

Note: If the Driving Predecessors flag is turned on, and the Project Complete milestone is selected, the tasks highlighted in orange will be the tasks on the critical path! These are the tasks driving the completion of the project.

 

Below is a simple schedule model example with all four toggles turned on.

Task 2 – Determine Project Scope is selected and the highlighting is for that task’s Predecessors, Driving Predecessors, Successors, and Driven Successors.

 

When we click on task D, the highlighting changes to reflect task D’s linking.
 

Critical Tasks Checkbox

This is an option that may be used to display the critical tasks in red in the Gantt Chart area. It is typically used primarily to print out Gantt reports. If you do not have a need for this, you may skip this section.

The Critical Tasks checkbox is accessed on the Format ribbon, in the Bar Styles section. If the box is checked, Microsoft Project will display red bars for all tasks that are critical.

In Microsoft Project, by default:

  • Critical tasks are defined to have a total slack of 0 days (or less).
  • Non-Critical tasks are defined to be any task that has total slack greater than 0 days, or is complete.

We have set up our schedule model using the Must Finish On Constraint Type to enable the correct Total Slack to be calculated whether it is positive, negative, or zero. Therefore, the Critical Tasks checkbox, by default, will only work for our project when we have negative or zero Total Slack on our critical path.

However, there are two ways that we can use the Critical Tasks checkbox even if we have positive Total Slack on our critical path.

1. The definition of what Microsoft Project considers critical is a configurable setting. We can change the setting for what is critical. This is done in your Project Options.

Click the File ribbon and select Options. Then select Advanced and scroll down to the very last setting.

You may set the value to your project’s smallest Total Slack (critical path) as found through Grouping described above (excluding the Target Complete which will have 0 days Total Slack). If you change the setting to this value, the tasks on your critical path will be highlighted in red even if they are positive. In our example from above, we would use 8 days.

You will, however, need to reset this value any time the Total Slack on your critical path changes to continue using the Critical Tasks checkbox, so the second approach may be preferred.

 

 
2. The second option is to temporarily Inactivate the Target Complete milestone that has been assigned the Must Finish On Constraint Type. This will recalculate the Total Slack values for all of your tasks based on there being no finish date constraint. As discussed previously, if there is no finish date constraint, the critical path will always have a Total Slack of 0 days and will therefore be highlighted by Microsoft Project based on its default setting.

To Inactivate the Target Complete milestone, select the Target Complete milestone. On the Task ribbon, in the Schedule section, click on Inactivate.

All fields for that milestone will be shown in gray with a strikethrough. The milestone in the Gantt Chart area is also shown in gray. If desired, you may now use your autofilter to hide the Target Complete milestone.

Inactivate treats the milestone as if it doesn’t exist. It is not considered in the backward pass calculation so the Total Slack for the critical path will be zero. Remember that you will not be seeing the Total Slack values based on the Must Finish On date constraint while the milestone is inactivated.

Once you have printed your Gantt Chart report, reactivate the milestone by clicking the Inactivate toggle again.

 
 
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