Shift Reasons are reasons as to why an assignment is requested and/or scheduled. They can be used to hide confidential information from other users.
A Shift Reason could be used when a provider is requesting to be out on LOA. What is visible on the request calendar would be LOA (or any other assignment choice) and then the detailed reason can be chosen and hidden from other users. Note: the LOA in this case would also be visible on the schedule and not the reason.
The picture above is a screenshot from the NSight Request page. This is an example of a provider requesting the assignment LOA, you will see highlighted at the bottom is a list of Shift Reasons. That provider can then pick the reason behind needing the LOA from the list of details. The screenshot below is what would be visible on the request calendar.