“…IR has been observed to be more effective and efficient for learning and retention of factual-level content than other flashcard techniques for students of different ages and ability levels (e.g., Burns, 2005; Burns et al, 2019; MacQuarrie et al, 2002). For example, IR has been used in research to improve performance with letter sounds (e.g., Volpe et al, 2011), sight words (e.g., Phipps et al, 2020), vocabulary (e.g., Petersen-Brown & Burns, 2011); and math facts (e.g., McVancel et al, 2018). In describing the cognitive underpinnings of IR, Varma and Schleisman (2014) argue that the superiority of IR over other flashcard techniques is likely due to the spaced and expanded structure of practice.…”