Using Intermediate Constraint Features in Microsoft Project

Our last post covered the basics of setting and entering constraints in Microsoft Project. This post will cover:

• Overriding a Task Dependency with a Hard Constraint
• Setting and Clearing Constraints Using a Split Window
• Clearing Constraints for Multiple Tasks

Overriding a Task Dependency with a Hard Constraint

A hard constraint is an inflexible limitation placed on the Microsoft scheduling engine that forces it to ignore certain task dependencies. If you do not have the Planning Wizard on, these changes may occur without your knowledge.

We use an example project to demonstrate this process:

1. Double-click a task to prompt the Task Information dialog box. In the example, we choose Conduct session (ID 16).
2. Click the Advanced tab.
3. From the Constraint type dropdown list, select “Finish No Later Than”.
4. From the Constraint date dropdown calendar, select a date in the future. In our example, we indicate that the task Conduct session must finish on or before December 12.
5. Click OK. If the Planning Wizard is on, it will prompt the following alert:

Figure 1.         Planning Wizard alert

6. Microsoft Project is alerting you to a potential scheduling conflict that has occurred because Conduct session is linked to another task. Click the Continue. A Finish No Later Than constraint will be set option button.

7. Click OK.  Notice the new icon in the Indicator column for the edited task—a small calendar with one red square []. This icon indicates the task constraint is inflexible.

8. Try increasing the duration of a predecessor task. In the example, we extend Conduct pre-interviews (ID 15) from 6 days to 10 days. Allow the schedule conflict and click OK.  What happens to the link between the two tasks?

Figure 2.       Schedule conflict caused by an inflexible constraint

9. Notice the schedule conflict in the visual overlap (inside the rectangle) between Conduct pre-interviews and Conduct session in our example project.

Setting and Clearing Constraints Using a Split Window

To manage constraints in a split window:

1. Select a task. From Task:Properties click the Details icon.  Your screen will resemble the following:

Figure 3.     Gantt Chart and Task Details Form

2. From the Constraint dropdown list in the bottom half of your screen, select Must Finish On for the selected task. Click OK. The button face will change from OK to Previous. If you do not assign a constraint date, Microsoft Project uses the already calculated date.

3. In the top pane, select another task with a constraint applied to it.

4. To remove the constraint, select As Soon As Possible from the Constraint dropdown list in the bottom pane. Click OK.

5. Double-click the window split bar to remove the split.

Clearing Constraints for Multiple Tasks

1. Make sure you are in the Gantt Chart view.

2. Select the Task Name column by clicking the column header.

3. From Task:Properties click the Information button.  You will be presented with the following dialog box:

Figure 4.     Multiple Task Information dialog box

4. Click the Advanced tab (if necessary).

5.  Select As Soon As Possible from the Constraint type dropdown list.

6.   Click OK.  Notice that any remaining task constraints have been cleared.

For a full rundown of all the constraint types, view our introduction to the topic.

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