To study your memory and sleep, use options available in SuperMemo in the following places:
You can use Tools : Workload (Ctrl+W) to inspect the daily and the monthly calendar of repetitions. You can view the number of repetitions scheduled, number of scheduled topics, number of scheduled items, as well as the record of past repetitions, and past retention, or how many new items were memorized.
Figure: The horizontal axis corresponds with the repetition number and the vertical axis represents intervals (logarithmic scale). Despite a popular belief, the semi-log scale does not produce a linear graph here. Clearly the increase in the length of intervals slows down with successive repetitions. Moreover, the graph corresponding with zero lapses (red curve), results from the superposition of items with lower and faster increase in intervals (determined by difficulty). The bell-shaped curve is determined by all contributing items (below repetition number 10) and then only by difficult items or items with low forgetting index for which the increase in the length of intervals is significantly slower (above repetition 10). To see the above graph in your own collection, use Tools : Repetitions graph on the browser menu
Inspect the timeline of repetitions and sleep:
Look for the best time for learning or sleep (see Sleep Chart for details):
See how your brain gradually loses its power during the day:
Look for the time of the day that should give you maximum learning power (Shift+click a day in the sleep timeline). See when your learning is not likely to be effective and when you should rather go to sleep: