Sandwich feedback: The empirical evidence of its effectiveness

This experiment tests the effectiveness of “sandwich” feedback. 91 university students solved 12 mathematical problems from the secondary-school curriculum. After the time limit, we assigned them randomly to one of three possible treatments. One group received corrective computer-administrated feedback, describing the mistakes with their methods and solutions. The second group received sandwich feedback, consisting of the same corrective part presented between two general positive statements unrelated to the participants’ actual performance. The third group did not receive any feedback. Afterwards, the participants had 10 min to prepare for the second set of similar problems. Participants who received sandwich feedback utilized more time on preparation and solved more problems from the second set than the participants from the other two groups. This study provides only partial evidence for the effectiveness of sandwich feedbacks as it tested the effect under one specific condition using computer-mediated written feedback on math test. Further replications are needed to test the effect under various conditions, to test various forms of sandwich feedback, to explain the mechanism of sandwich feedback and to show whether the effect of sandwich feedback is caused by the specific sequence of feedback components or by mere presence of positive statements.