Spaced retrieval practice consists of repetitions of the same retrieval event distributed through time. This learning strategy combines two “desirable difficulties”: retrieval practice and spacing effects. We carried out meta-analyses on 29 studies investigating the benefit of spacing out retrieval practice episodes on final retention. The total dataset was divided into two subsets to investigate two main questions: (1) Does spaced retrieval practice induce better memory retention than massed retrieval practice? (subset 1); (2) Is the expanding spacing schedule superior to the uniform spacing schedule when learning with retrieval practice? (subset 2). Using meta-regression with robust variance estimation, 39 effect sizes were aggregated in subset 1 and 54 in subset 2. Results from subset 1 indicated a strong benefit of spaced retrieval practice in comparison with massed retrieval practice (g = 0.74). Results from subset 2 indicated no significant difference between expanding and uniform spacing schedules of retrieval practice (g = 0.034). Moderator analyses on this subset showed that the number of exposures of an item during retrieval practice explains inconsistencies between studies: the more learners are tested, the more beneficial the expanding schedule is compared with the uniform one. Overall, these results support the advantage of spacing out the retrieval practice episodes on the same content, but do not support the widely held belief that inter-retrieval intervals should be progressively increased until a retention test.

间隔检索练习包括在时间上分布的相同检索事件的重复。这种学习策略结合了两个“理想的困难”：检索练习和间隔效应。我们对 29 项研究进行了荟萃分析，这些研究调查了间隔检索练习对最终保留的好处。整个数据集被分成两个子集来研究两个主要问题：（1）间隔检索练习是否比大量检索练习更能诱导记忆保持？（子集 1）；(2) 在检索练习中学习时，扩展间距表是否优于统一间距表？（子集 2）。使用具有稳健方差估计的元回归，子集 1 中汇总了 39 个效应量，子集 2 中汇总了 54 个效应量。g  = 0.74）。子集 2 的结果表明，检索实践的扩展和统一间隔时间表之间没有显着差异（g  = 0.034）。主持人对该子集的分析表明，检索练习期间项目的暴露次数解释了研究之间的不一致：测试的学习者越多，扩展时间表与统一时间表相比越有利。总体而言，这些结果支持将相同内容的检索练习片段间隔开的优势，但不支持广泛认为的检索间隔应该逐渐增加直到保留测试。