The oral exam also helps reduce (although it does not eliminate) the risk of granting a degree to a candidate who has had the thesis or dissertation ghostwritten by an expert.
There is a small but growing body of literature on the use of oral examinations in undergraduate education in the English speaking world.
Some medical schools use oral exams for second and third year students to test knowledge but also the ability to respond on the spot.
Some universities allow the option of either taking written and oral exams or completing a project or thesis, but occasionally, all three are required for graduation.
[1] An oral exam is also carried out by the Maritime and Coastguard Agency in the UK for the purpose of issuing certificate of competencies for Merchant Navy deck and engine officers.