Tony Gardner-Medwin has kindly given permission to post some fragments he’s put together of an informal review by Ahlgren (1969) of early work involving confidence
See here for the article which consists of some collated remarks delivered in the symposium “Confidence on Achievement Tests — Theory, Applications” at the
1969 meeting of the AERA and NCME.
You can see a lot more about Certainty-based marking / Confidence-based marking / (CBM) on Tony’s University College of London website: http://www.ucl.ac.uk/lapt/. His site contains and links to many publications on CBM, and information on the LAPT (London Agreed Protocol for Teaching) software which uses CBM in the presentation of learning resources.