“…For the simulation setting, studies frequently used designs in which training sessions were distributed within a single day 56,75,88,92,95,100,106 (n = 7) or within a set number of consecutive days, weeks or months 56,67,68,76,86-88,93,95-100,106 (n = 15). Notably, there were numerous differences in the number of training sessions, total training time and duration of intervals.For the classroom setting, most studies described the use of interim (eg cumulative) testing58,61,62,65,66,70,103,[107][108][109][110][111][117][118][119] (n = 15) to enhance long-term retention of to-be-learned information. Other applications of spaced learning in the classroom involved the distribution of teaching or learning sessions over multiple days60,72,112 (n = 3), weeks49,50,59,73 (n = 3), or months 73 (n = 1).…”