Negative Lags - Relationships With a Lag Duration of Less Than 0 Section of the Schedule Check Report Dialog Box

Overview

Use this section to identify relationships with negative lags. Negative lags can affect critical path and distort total float. When activity durations change, activities with negative lag can be scheduled unrealistically. Negative lags can be used to schedule overlapping activities. For example, when digging a trench, workers can start laying pipe in the completed sections of the trench while the rest of the trench is still in progress. To avoid the distortion that negative lag can cause, you might consider using positive lag on a Start to Start relationship rather than a negative lag on a Finish to Start relationship.

Only a subset of all the internal and external links in the open projects are checked. Any links between activities that both have actual finish dates are removed from the subset to create the list of links checked for negative lag. The Actual percentage is calculated as the number of links found that match the check divided by the total number of subset links checked.

Screen Elements

Predecessor Project ID field

The identifying code for the project containing the predecessor activity that failed the check. Click this link to view the predecessor project.

Predecessor Activity ID field

The identifying code for the predecessor activity that failed the check. Click this link to view the predecessor activity.

Predecessor Activity Description field

The brief description of the predecessor activity. Click this link to view the predecessor activity.

Relationship Type field

The type of relationship between two activities.

Valid values are:

Finish to Start: The successor activity cannot start until its predecessor finishes.

Finish to Finish: The successor activity cannot finish until its predecessor finishes.

Start to Start: The successor activity cannot start until its predecessor starts.

Start to Finish: The successor activity cannot finish until its predecessor starts.

Lag Duration (hours) field

The time in hours between the start or finish of the activity and the start or finish of the predecessor successor.

Successor Project ID field

The identifying code of the project that contains the successor activity. Click this link to view the successor project.

Successor Activity ID field

The identifying code of the successor activity. Click this link to view the successor activity.

Successor Activity Description field

The brief description of the successor activity. Click this link to view the successor activity.

Getting Here

Click Projects.
On the Projects navigation bar, click Activities.
1. Click the Actions menu and select Check Schedule, then select View Report.

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