The CPM Checker is a unique and powerful tool. It helps you to make sure that your schedule makes sense, is easy to maintain, and does not violate the Critical Path Method.

Settings

Click CPM Checker Settings on the Tools menu to change the settings and bounds for the CPM Checker:

• Maximum Open Starts: The maximum number of activities allowed to have no predecessors. Too many start points in your schedule can make it difficult to calculate float and can skew the critical path.
• Maximum Open Finishes: The maximum number of activities allowed to have no successors.
• Excessive Free Float: The maximum amount of free float activities are allowed to have.
• Excessive Total Float: The maximum amount of total float allowed.
• Excessive Duration: Single activities should not last longer than this in the schedule. If so, perhaps the activity should be broken up to show more detail.
• Excessive Lag: The maximum lag allowed.
• Maximum Constraints: The maximum number of constraints allowed in the schedule. Constraints can lead to ineffective and difficult schedules if there are too many of them and should be kept to a minimum.
• Minimum Percent Critical: No less than this percentage of the schedule should have activities that are part of the critical path.
• Maximum Percent Critical: No more than this percentage of the schedule should be critical. If there are too many critical activities, it can be difficult to identify the true critical path in the schedule.

The values you use in the CPM Checker settings determine how the CPM Checker looks at your schedule. If any activities or relationships violate the bounds set in the CPM Checker settings, a balloon note will be shown pointing to the violating activity. If the percentage of critical activities is greater than the Maximum Percent Critical setting, you will get a message box informing you of the problem when you start the CPM Checker.

Running the CPM Checker

To start the CPM Checker, click Run CPM Checker on the Tools menu. If too much of the schedule is critical, there will be a dialog box informing you of this when you start the CPM Checker. Once started, the CPM Checker goes through each of the various checks showing you a balloon note about any CPM problems that are found. On a balloon note there is a title describing the type of problem found and a more detailed description explaining what the problem is and what needs to be done about it.

There are several buttons on the balloon notes

• Recheck: Restarts the CPM Checker from the beginning.
• Explain: Allows you to explain the reasoning for certain items such as constraints, excessive free float, excessive total float, excessive duration, and excessive lag.
• Skip: Skips this CPM problem until the next time the CPM Checker is run.
• Stop: Stops the CPM Checker.

Note: You can stop the CPM Checker at any time by clicking Stop CPM Checker on the Tools menu.

Reviewing CPM Explanations

After you have run the CPM Checker, you can review the explanations you provided while running the CPM Checker. To review them, just click Review CPM Explanations on the Tools menu. The Review Explanations dialog will allow you to view and edit the explanations. You can delete an explanation by checking the Delete this Explanation checkbox and subsequently clicking OK. By clicking Previous and Next you can navigate through the explanations. You can save any changes to the explanations that you have made by clicking OK. If you click Cancel, none of your changes will be saved.