I’ve posted before about the fact that whilst students usually engage quite well with formative-only iCMA questions, when the going gets tough, they are inevitably more likely to guess than is the case when the mark counts. When I eventually get to the end of my course writing (and associated preference for blogging about things to do with maths misunderstandings, on the basis that this is relevant for the course writing too), I will talk about our changes of assessment strategy in the Open University Science Faculty. For now, I just want to reflect on the size of the formative vs summative effect. Don’t treat this too seriously, but I think the answer to ‘how big is the effect’ may be 3%. Read on.
In the practice assessment, 74.3% of responses were correct whilst 6.2% gave the number given in the question (so for this variant, they gave an answer of 4 – presumably guessing). In the summative equivalent, 77.7% of responses were correct whilst 3.3% gave the number given in the question.