Retrieval practice may be less effective without feedback

A systematic review by Agarwal et al (2021) found that experiments which did not include feedback mostly (4/6) produced small effects.

Agarwal et al. - 2021 - Retrieval Practice Consistently Benefits Student Learning

• Weak evidence in Kang et al. - 2007 - Test format and corrective feedback modify the effect of testing on long-term retention, comparing results in two experiments, finds that provision of feedback led to greater final test performance (but only for short-answer retrieval format, not multiple choice).