It tested well. Users scored it highly. In production it takes longer than the system it replaced.
That combination is common enough to have its own signature, and it has nothing to do with the interface.
Usability asks whether a person can operate this system to perform a task.
Workability asks whether the work can be performed — in this organisation, with the information that is actually available at the moment it is needed, by somebody with the authority to do it, over the timespan the work really occupies.
Can they complete the task when half the information has not arrived yet? How many times will they be interrupted, and what survives the interruption? Is there a route for the case that fits no error message? Do they have the authority to do what the screen is asking?
None of those questions is answerable in a usability session, because a test environment is specifically designed to remove the conditions that produce them.
In your next test, interrupt somebody. Take them out of the room for twenty minutes without warning and see what is there when they come back.
The distinction, and how to test for the second one, is chapter 13 of Built to Be Used.
#UX #ProductDesign #UserResearch
This article accompanies the book Built to Be Used.