> the student is clearly failing to answer simple questions, it’s quite hard for them to argue they were treated unfairly. I know you didn't quite say that, bu

> the student is clearly failing to answer simple questions, it’s quite hard for them to argue they were treated unfairly. I know you didn't quite say that, but to be clear: Fairness isn't defined by someone being able to argue that they were treated unfairly. You still have room for bias in how you treat weaknesses in student answers, and few students are going to give perfect answers for everything. And even without any specific-to-the-student bias I'm going to be more consistent in grading the same question if I go through a stack of written answers en-bloc than if I grade replies with hours or days inbetween. Randomized questions also has potential for bias that feels like it could be stronger than question selection for a written exam. That's not to say there isn't value in doing oral exams, but they are not the solution for everything either.