We’ve known the benefits of retrieval practice for years, no, decades. Still, for sure after the replication crisis, it’s always good to check if it’s still standing. This new systematic review published in preprint confirms: yes, it is.

Does retrieval practice improve student learning in school and classroom settings? Based on our literature review, our response for researchers and educators is an unequivocal “yes.” We found a wealth of evidence, based on medium to large effect sizes, that retrieval practice improved learning for a variety of education levels, content areas, experimental designs, retrieval practice timing, final test delays, retrieval and final test formats, and the timing of feedback.

But… as any good review, it also shows that there is still research lacking. I do think this is the most important part of the review, therefor I give this summary of the eight recommendations Agarwal et al make:

First, the field needs more applied research investigating varying delays between retrieval practice and the final test. We found larger effect sizes at shorter delays (1–3 days) and smaller effect sizes at longer delays (end of the semester). In other words, results from our review of the literature indicate the opposite of what is typically found in laboratory studies, where benefits from retrieval practice are larger after longer delays…

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Second, classroom research specifically investigating the provision and timing of feedback is needed. Although feedback is a key component of educational settings, classroom studies that directly manipulated feedback (e.g., immediate vs. delayed) were notably absent from our literature search.

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Third, comparison conditions for future research on retrieval practice should more closely mirror common classroom practices. We found that many studies in our literature review compared retrieval practice to re-reading.

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Fourth, future research should also examine factors unique to applied settings including class size (e.g., lecture classes vs. small classes), whether retrieval practice was anticipated (e.g., “pop quiz” vs. announced in advance), whether the final test was cumulative, and whether performance on initial retrieval practice counted towards students’ grades.

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Fifth, additional research is needed in non-science content areas, such as skills-based

earning, mathematics, the humanities (writing, literature, essays), and foreign language vocabulary. Thirty-five out of the 50 experiments reviewed were conducted in science or psychology courses. We were particularly surprised that none of the experiments meeting our screening criteria included foreign language learning, considering the frequent use of these materials in laboratory experiments.

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Sixth, applied research in education should also take into account the role of the teacher- researcher as a modulating factor for student learning outcomes, also known as the Hawthorne Effect or “participant reactivity” (Diaper, 1990; Paradis & Sutkin, 2017). This information was inconsistently reported in the studies reviewed, unfortunately.

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Seventh, collaborative retrieval and online quizzes are common in educational settings and it would be beneficial to know when and how they increase student learning.

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As our final recommendation, applied research on retrieval practice must be conducted with diverse student populations. We found that only three out of 50 experiments that met our screening criteria were conducted outside the United States and Western Europe (Turkey, Pakistan, and Taiwan), while 94% of classroom research on retrieval practice was conducted in WEIRD countries (western, educated, industrialized, rich, democratic countries…

Abstract of the review study:

Given the growing interest in retrieval practice among educators, it is valuable to know when retrieval practice does and does not improve student learning—particularly for educators who have limited classroom time and resources. In this literature review, we developed a narrow operational definition for “classroom research” compared to previous reviews of the literature. We screened nearly 2,000 abstracts and systematically coded 50 experiments to establish a clearer picture of benefits from retrieval practice in real world educational settings. Our review yielded 49 effect sizes and a total n = 5,374, the majority of which (57%) revealed medium or large benefits from retrieval practice. We found that retrieval practice improved learning for a variety of education levels, content areas, experimental designs, final test delays, retrieval and final test formats, and timing of retrieval practice and feedback; however, only 6% of experiments were conducted in non-WEIRD countries. Based on our review of the literature, we make eight recommendations for future research and provide educators with a better understanding of the robust benefits of retrieval practice across a range of school and classroom settings.