CBM can be applied to any online quiz. In addition to entering the answer to their question, the student also tries to estimate how certain they are that they have got the answer right, for example on a scale of low, medium or high.

Then, their mark for the question is adjusted based on their certainty. Suppose the basic mark for the question was 1. Then:

• If they only had low certainty, then they get 1 for a right answer, and 0 for a wrong answer, as usual.
• If they expressed medium certainly, then the get 2 for a right answer, but -2 for a wrong answer.
• If they were highly confident, then they get 3 for a correct answer, but -6 for a wrong answer.

The scores (which are, of course, just one possible choice, but a good one) mean that if you think the chances you are right are more than 80%, then you should choose high. If you think the odds are more that 67% then choose medium, and if it is more of a guess than that, choose low.

CBM encourages students to reflect on the reliability of the knowledge they have. Tony Gardner Medwin, the CBM advocate who introduced me to the concept, works in medical education. I certainly would like any doctor who treats me to be honest with themself when they are shur and when they are guessing. CBM also adds richness to simple question types like multiple choice.

See http://moodle.org/mod/forum/discuss.php?d=61169 and http://www.ucl.ac.uk/lapt/ for more information.