In one study, students were divided into three groups and tested twice:
- Group 1 got only feedback on their work but no marks;
- Group 2 got only marks, without any feedback whatsoever, and
- Group 3 got both marks and feedback.
Group 1 improved by a solid 30% on average, while Group 2 did not improve at all. This makes sense, as they weren't given any suggestions as to how they would be able to improve. However, I was very surprised to learn that Group 3 performed just like Group 2 and didn't improve at all!
Dylan Wiliam sums up the findings in his paper 'Keeping learning on track: Formative assessment and the regulation of learning':
If you're interested in finding out more, read Dylan Wiliam's paper. Pages 24 – 28 give a particularly valuable insight into the quality of feedback.