I seem to remember some medical related multiple choice tests in the UK use a mechanism of +1 for correct , 0 for unanswered , -1 for incorrect.

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bArray 23 minutes ago | parent | next [-]

Typically you have -1/N for incorrect selection, where N is the number of choices. For N=4, you would grade incorrect answers as -0.25.

If you have a person taking an exam that is not confident in themselves or generally knows the subject area, you don't want to negatively impact educated guessing.

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CGMthrowaway an hour ago | parent | prev [-]

A system like that seems especially appropriate for a practice where the foundational principle is "do no harm."

	▲	bee_rider an hour ago \| parent \| next [-]
		Would probably be applicable to engineers as well, or any other field where the practitioner has an obligation to be aware of the limits of their competency.
	▲	DANmode 22 minutes ago \| parent \| prev [-]
		and yet.