Certainty based marking (sometimes erroneously refered to as competence based marking) is an advanced scoring strategy that requires learners to classify how certain they are of their response when submitting it. A higher certainty carries a possible higher reward, but also a much higher penalty when the response is incorrect. As such certainty based marking can mitigate guessing on constrained response items, but it is also ver useful as a stimlans for reflection. More information can be found in articles like "Certainty-Based Marking (CBM) for Reflective Learning and Proper Knowledge Assessment".
There are other interesting options to explore however, and I was reminded of one when I read
Conscious Competence - a reflection on professional learning, which talks about the conscious competence model. In my opinion, these two fit together very nicely, as depicted in the diagram below. Candidates providing the wrong answer, but indicating a high degree of certainty about their answer can be considered as 'unknown incompetent', as they seem unaware of their misconceptions. Candidates providing the wrong answer with a very low degree of certainty have progresssed to 'known incompetence', as they have at least correctly identified their lack of understanding. When providing the correct answer with a low degree of certainty, learners can be assigned to the unknown competence stage untill finally tey progress to known competence if they provide a high certainty correct response.
Although I am still looking for an opportunity to actually try this in practice, I think it has a lot of potential in spporting an integrated formative and summative assessment strategy.