In certain situations, you may want to connect two projects together. This requires using external dependencies.
You may have two projects that affect one another. Instead of creating one master schedule you may want to keep the two projects separate and unique. But how do you model the interdependency between the two projects? This is done by creating an external dependency that links the two projects together. In other words, you want to create a cross-project link.
This article demonstrates how to create an external dependency between two unique projects.
We have in Figure 1 our demonstration project, Pipe Installation.
Figure 1
This is a piping installation project, which requires excavation for a pipe trench. We want to link or connect this project to the follow on project, Backfill & Paving, Figure 2.
Figure 2
As demonstrated in the view tab, window ribbon group, and switch windows, Figure 3, both projects are open in Microsoft Project.
Figure 3
They also are located in the same folder.
We switch to the Backfill & Paving project, Figure 3. We want to link Start Backfill, task 1, in Backfill & Paving to End Pipe Installation, task 11, in Pipe Installation. In Figure 4 we highlight the Start Backfill task.
Figure 4
Continue and select the task tab, properties ribbon group, and information, Figure 4. In the task information dialog, Figure 5, we type in the ID name starting with the filename, Pipe Installation. We add a backslash, and enter task ID 11 for our End Pipe Installation task.
Figure 5
As viewed in Figure 6, our external dependency has been created.
Figure 6
We view our external dependency in the task table and Gantt chart, Figure 7.
Figure 7
In Figure 8, we return to the Task Information dialog and define a 4-day lag on our external dependency.
Figure 8
In Figure 9 we observe on the Gantt chart the 4-day lag between End Pipe Installation and Start Backfill.
Figure 9
In Figure 10, we switch to the Pipe Installation project and note the external dependency, including 4-day lag, between End Pipe Installation and Start Backfill.
Figure 10
Microsoft Project also has a dialog for viewing external dependencies. Select the project tab, properties ribbon group, and links between projects icon, Figure 11.
Figure 11
In Figure 12 we see the external successor to End Pipe Installation is Start Backfill, which includes a ‘FS + 4d’ relationship definition.
Figure 12
Summary
Microsoft Project supports the definition of external dependencies or cross-project links. The key is to locate both schedules in the same folder then type in the project file name, a backslash, and a task ID to define the external dependency. It is also possible to edit cross-project links and include a lag. External dependencies appear on the task table and Gantt chart, and are viewable in the Links Between Projects dialog.