Sleep and learning research. You can join the program!

New article by Dr. Piotr Wozniak: The true history of spaced repetition
Important! For the newest version of this article, see the up-to-date original version.

You can contribute to the understanding of the impact of sleep on learning! Here is how: 

What you need to participate

  • SuperMemo 2006 with at least 3 months of learning data (you can also use older versions of SuperMemo, or SuperMemo 98 freeware, however, older SuperMemos do not record essential circadian timing details)
  • SleepChart with at least 3 months of sleep data. You can also submit your data in non-SleepChart formats that will later be converted to SleepChart. If your sleep is very regular (e.g. you are always up at 6:00 on weekdays, and always get up at 9:00 on weekends), your learning data alone might also be of value

What you get in return

  • enormous satisfaction from your contribution to the science of sleep and learning!
  • personalized report on your sleep and learning (please note that due to a substantial effort needed to analyze each individual case, the number of personalized reports may be limited to a hundred submissions in first-come first-served order)
  • rewards (limited number). These will not be revealed to prevent submission of cooked reports. Rewards are not monetary and will only be appreciated by true SuperMemo maniacs. Please note that cooked data can easily be detected numerically. Fishing for rewards will only waste time on both sides

How to submit your data

Send your sleep.tim, <collection>.kno and RepetitionHist.dat files via e-mail: 

  1. Please use sleepYEAR @ to submit your data (or get further help). Remove spaces around the @ sign and replace YEAR with the current year to convert this address into a valid e-mail address
  2. Send your RepetitionHist.dat file from your collection's info folder. This file reveals only grades, timing of repetitions, etc. (as seen in Repetition history, Ctrl+Shift+H). This file does not reveal any personal data nor contents of your collection
  3. Send your collection's kno file (e.g. MyCollection.kno). This file is only needed to read the first day of your learning process (all data in RepetitionHist.dat is relative to the first day of learning). This file also reveals some of your learning statistics: number of elements, average forgetting index, Burden, etc. (as seen in Statistics window, F5). It does not reveal any personal data nor contents of your collection 
  4. Send your tim file from SleepChart (e.g. sleep.tim). This file reveals the timing of your sleep blocks as displayed in SleepChart
  5. If you have specific questions to ask about your own sleep and learning, please include them in your mail. The software used in the analysis of data is constantly being improved to include new analytical angles
  6. If you do not receive an acknowledgement of receipt, please re-check the e-mail address and send your mail again. If you still do not get a confirmation, use other addresses at or leave a note in SuperMemopedia

If you do not have your own data yet

  • download SleepChart and use it daily, register all sleep blocks, even a 2 min. nap in front of a TV set (the address is:
  • use SuperMemo 2006 as often as possible and in as many small blocks throughout the day as possible (even 2-3 minutes of learning can produce a valuable point of data)
  • important: if unavoidable, you can skip learning on selected days; however, if you skip days in your SleepChart data, the value of your dataset will drop dramatically

Thank you in advance for submitting your data!