Data Type Yes/No (Yes/No field: A type of field with content set to either Yes or No; also known as a Boolean field or a True/False field. For example, the Recurring field indicates whether the task is a recurring task.)
Entry Type Calculated (calculated field: A field in which the value is determined by Project based on information in other fields. Project may recalculate the value automatically or when you specify, depending on your choice of calculation settings.)
Description The External Task field indicates whether the task is linked (linking: In a project, establishing a dependency between tasks. Linking tasks defines a dependency between their start and finish dates. In OLE, establishing a connection between programs so that data in one document is updated when it changes in another.) from another project or whether it originated in the current project.
How Calculated If the task is linked from another project, that is, if it is a predecessor or successor from another project, the value is Yes. If the task was created in this project, the value is No.
Best Uses Add the External Task field to any task sheet (task view: A view that displays task information. Task views include three task forms; examples include Calendar, Detail Gantt, Gantt Chart, Milestone Rollup, PA_PERT Entry Sheet, Task Entry, Relationship Diagram, Task Sheet, and Task Usage.) when you want to view whether tasks are linked from other projects. Also add this field when you want to sort, filter, or group tasks by whether they're linked from other projects.
Example In your project, you have a number of task dependencies (task dependencies: A relationship between two linked tasks; linked by a dependency between their finish and start dates. There are four kinds of task dependencies: Finish-to-start [FS], Start-to-start [SS], Finish-to-finish [FF], and Start-to-finish [SF].) to and from tasks in other linked projects. You want to see which tasks are external to this project. Add the External Task field to the Entry table of the Gantt Chart.
Remarks By default, external tasks are displayed with a different text color in tables. You can change the text color of external tasks in the Text Styles dialog box.
Also by default, external tasks are displayed with a different Gantt bar color. You can set the bar style you want for external tasks in the Bar Styles dialog box.