If you add Job Evaluations or Gender data before adding Employee or Job data the compensation tool automatically creates a default incumbent year that is the current year minus one year (if it 2021, the default incumbent year becomes 2020).  The incumbent year is required as soon a Job is entered in any section.  

You can change the incumbent year once you start adding additional years to your project.  Changing the incumbent year can be done in the Project Management section.

NOTE: The incumbent year cannot be deleted from a project, an incumbent year is always required in a project, however when you have more than one year in your project you can change the incumbent year and then delete the previous incumbent year.