Average retrievability not equal to average predicted retention

Good morning guys!

I posted about this on reddit, and was told to post again here for more help. I have been unable to reach my target retention now for many months unfortunately. I have been very good with my reviews except for a few days after taking step 1, but I can never hit the desired 90% and have been in the 85ish range for a very long time. I have been using FSRS since the github days and had excellent retention for the first few months. I’d love any suggestions. Any ideas @LMSherlock ?

You are not studying any deck and the “retrievability” of the cards is slowly falling.
Show us the Future Due chart, are there any backlogs?

So even before this point with zero backlog due (I now have a backlog because I rescheduled to 94% retention with the hope itll bring me up so I have it in a filtered deck. And even before I had the backlog I wasn’t missing days. I will say that some cards for me are really really hard and I get them wrong all the time, but it feels like the algorithm treats them like other cards and when I am relearning it shows me them at the same frequency.

I apologize I realized you wanted to see backlogs as well. I do currently have a backlog because of the rescheduling unfortunately, but I have not had one for many months prior.

Let’s try another way. Sort your cards in the browser by R.

Then you can see what kind of cards they are with a small Retrievability. Another option to do this is to click on the chart.

They’re all actively suspended cards right now.

I guess you don’t have to worry. Most likely ANKI shows statistics with suspended cards and FSRS4Anki Helper without.

  • Average predicted retention reflects the percentage of cards that you would recall correctly if you were tested today.

You have it equal to 94.83%


That’s what I thought too, but the discrepancy is too big.

Oops. I forget to update this function…:sob:

Fixed in Fix/calculate current retrievability with FSRS-4.5 by L-M-Sherlock · Pull Request #192 · open-spaced-repetition/fsrs-rs (github.com)

I was just about to ask about this issue. Guess I don’t have to now right? In most my decks retention is around 70 percent when it should be around 85 per cent. I have been using FSRS for a couple of months now and retention is bad it seems. (bad=lower than expected)

Thank you for the confirmation! I see you updated the fsrs Rust package, and updated the Anki to use the new package. Do you happen to know the Anki release schedule and how I can start using the fix now?

My guess is this month. Anki 24.05 is coming, and my patch will be included.

Thank you so much! You’re doing absolutely amazing work and have really helped to revolutionize learning (especially for med students). I was talking with my fiancé about your work (she’s a software engineer at FAANG and follows your work from more of coding side), and we were talking about how lots of research/open source devs often struggle to get their work monetized, so I hope you find some sort of way because this technology is the future of education. Thanks again!


Jarrett has a job at Maimemo, it’s like Chinese Duolingo. He also gets donations via ko-fi, but apparently he made less money form that than his monthly salary. Than there’s also this

It’s pretty hard to monetize open source stuff, yeah.
David (AnkiDroid dev) said, quote, “AnkiDroid makes ~$0.01/user/year”.


Unfortunately I can’t think of an easy solution. The ANKING went off and made his own company, it’s something that the team could consider in the future, even if it’s for a consultant role in med ed or even educational game development with built in space repetition (thinking of a company like levelex with some space repetition built in or something). Just a thought is all. I’d love to see the team make it big, they deserve it more than a lot of people who have made way more doing way less for humanity.

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