SM-15

Unfortunately there's no single good source for this; 30% is just an approximate aggregate figure I've come up with after seeing various people's posts on different sites. Some things I could find just now: Anki vs. SM-8: https://anki.tenderapp.com/discussions/effective-learning/12... SM-2 vs. SM-17: https://supermemo.guru/wiki/Universal_metric_for_cross-compa... Anki vs. custom machine learning scheduler: https://old.reddit.com/r/Anki/comments/d0i8uy/improved_algor... Anki vs SM-17: https://unrelatedwaffle.medium.com/battle-of-the-spaced-repe... SuperMemo seems to fall behind Anki in the short term (<6 months), but eventually makes up for it. Some of the links reflect that. As for open-source implementations, there this: https://github.com/slaypni/SM-15

SuperMemo2 You can find lots of different implementations on gitbub. https://github.com/search?q=Supermemo2&type= Just bear in mind that SM-2 is quite outdated. I've found a more recent version but I'm not sure how accurate it's. https://github.com/slaypni/SM-15

There seems to be an unaddressed need for a well-maintained library implementing spaced repetition algorithms. I have seen implementations for SM15[0] and SM2[1][2] around but nothing that provides multiple implementations and a consistent API on top. If there was a library like that, a tool like SpacedTime could use it easily (currently it uses fibonacci sequences when determining how soon to recall). [0] https://github.com/slaypni/SM-15, https://news.ycombinator.com/item?id=9844613 [1] https://github.com/walterscarborough/LibSpacey [2] https://gist.github.com/doctorpangloss/13ab29abd087dc1927475...

Last year, I have developed a JS library SM.js (https://github.com/slaypni/SM-15) which is based on the algorithm used in the latest SuperMemo. I have also developed a web service (http://slaypni.github.io/flashward/) for memorizing Foreign words using the library. Through the experience of using it by myself, I felt that spaced repetition helped me to remember many words for learning English. I am feeling that most (free) SRS are using relatively simple algorithms (for example, Anki is based on SM-2 which is developed in the late1980s). Although I am not sure SM-15 is better enough, there could be some room to improve it. It is nice if the library was helpful for some developers who create new SRS.