I’ve ranted about the lack of diversity of Spaced Repetition algorithms before. Since that post, I’ve realized three things:
- I should probably do some more market research on whether it is actually true that everyone under the sun uses SM-2
- Spaced Repetition can be understood as a Queue Theory problem
- There are some people that do build some wild SR algorithms out there
This post is dedicated to the first point. I asked ChatGPT for Spaced Repetition software until it ran out of ideas, and will now attempt to research what algos they are using. It’s likely not exhaustive. Anyways - if such an overview is of value to you, here you go:
While the research took longer than I expected, the list turned out to be surprisingly short. At some point I started ignoring apps where nothing at all could be found regarding their algos, to be fair.
Another serious limitation is that I lazily used ChatGPT to get the initial list, which at this point has limited knowledge of the post 2018 world, an god knows what other biases.
- I’m surprised by how simple some algos are, such as Mochi’s. I think a well implemented SR simulator is my next project. I want to see if naive methods like that are actually worse than the outdated but revered SM-2.
- There is definitely room for improvement in this industry, SR-algorithm-wise.
- The good stuff is either to be found in papers, in very small or new tools that ChatGPT doesn’t know, or does not exist.
Thanks for reading. Please let me know if you find any errors or omissions. Until next time!