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About Dependency Relationships

A dependency provides you with a means of ordering the relationship, timing, and logical sequence between a task within the same project (internal dependency) or between a task in your project and a task that is external to the project (external dependency). When you create an external dependency, you add the subproject task to your master project. Creating dependencies does not automatically adjust your project plan; you must autoschedule your project.

A dependency links one task to another where the start or finish date of the second task (the successor) is constrained by the start or finish date of the first task (the predecessor). Define dependency relationships to ensure that you can evaluate the cascading impact of changes to tasks when autoscheduling. If a task is isolated and is not needed by or is not dependent on another task, it can be independent.

You can create the following types of dependencies to establish the relationship between the start and finish dates of dependent tasks:

• Finish-Start. The predecessor task's finish date determines the successor task's earliest possible start date. With this dependency type, the successor task cannot start until its predecessor task finishes.
• Finish-Finish. The predecessor task's finish date determines the successor task's earliest possible finish date. With this dependency type, the successor task cannot finish until its predecessor task finishes.
• Start-Start. The predecessor task's start date determines the successor task's earliest possible start date. With this dependency type, the successor task cannot start until its predecessor task starts.
• Start-Finish. The predecessor task's start date determines the successor task's earliest possible finish date. With this dependency type, the successor task cannot finish until its predecessor task starts.

The dependency type that is used when creating dependency links is the default dependency type you defined on the Defaults tab on the Options dialog box. Open Workbench's default dependency type is Finish-Start. Once you create the dependency, you can edit the dependency type.

More information:

Create Internal Task Dependencies

Create External Task Dependencies

Define the Default Dependency Options

About Task Dependencies Properties

About Master Project and Subprojects

Autoschedule Projects

How Critical Path is Calculated