So I am using the FSRS on anki right for the ankingmcat deck. My mcat test is in 4 months so would it be smart to set my maximum interval in the advanced options to 4 months then? Would this make the FSRS help me to retain all the information within 4 months?
Hello,
No, it would not be recommended to set the max interval in that way, as it is not designed, or intended, to be used for a particular due date. There is a longer explanation I can give, if you’re interested in the nuts and bolts, but the short version is that the max interval isn’t used in that way and should be set to 1 year or longer (it is independent of timeline horizon for an exam).
It’s also probably worth pointing out that max interval has no impact on retention, or FSRS, really.
Please let me know if that answers your question, and if there’s anything else I can help with. 
could you please give me the thorough explanation? I am just asking this because when I was using FSRS with the 5 year max interval, it would put some of the cards scheduled for like 2 years later, if I clicked easy on them for instance. But this implies I will never see the card again since my mcat is in 4 months. Does it do this because it believes I have fully memorized that card and I essentially do not need to see it again(or at least in 2 years).
Okay, so let’s imagine you set a max interval of four months.
And today, you see a card for the first time. I’m just going to make up some numbers as an example:
Card 1: you introduce this card today for the first time
- First time - you see it again in 3 days.
- Second time - you see it again in 11 days.
- Third time - you see it again in 21 days.
- Fourth time - you see it again in 30 days.
- Fifth time - you see it again in 2 months.
- Sixth time - you see it again in 3 months.
- Seventh time - you see it again in 4 months.
- Eighth time - you see it again in 4 months (this is the max interval, so it can’t go out further than that).
So, in the end, by the time you get to the max interval (the 7th repetition), it’s not sending it out 4 months from your start date, it’s sending it out 4 months from whatever day it is that you finally hit the max interval.
In the above example, that means that, before you even get to the max interval, it’s already scheduled out 7.25 months, a full 3+ months after your exam date.
Card 2: you introduce this card for the first time two months from now
- First time - you see it again in 3 days.
- Second time - you see it again in 11 days.
- Third time - you see it again in 21 days.
- Fourth time - you see it again in 30 days.
- Fifth time - you see it again in 2 months.
- Sixth time - you see it again in 3 months.
- Seventh time - you see it again in 4 months.
- Eighth time - you see it again in 4 months (this is the max interval, so it can’t go out further than that).
This card follows the same pattern, but because you introduced it two months later than the first card, it’s going to be scheduled out 9 months later, a full 5+ months after your exam. In this case, it won’t even reach the max interval by the time you take your exam.
Again, this is because a maximum interval is not related to an exam date.
From here, the temptation is to think “okay, well why not just set the maximum interval to 2 months then? Or 1 month?” And this would also likely be unwise. Because now you’re going to see every single card with a max cap of 4 weeks, or 8 weeks, or whatever it may be, and there is a 100% chance you don’t want, or need, to artificially cap every single card at such a small interval.
First, again even capping it at two months does not necessarily mean anything related to your actual exam date. And, it should be pointed out: because Anki is a spaced repetition program you’re already going to see all of your cards before your exam, and some of those cards will, naturally, eventually get scheduled out further than your exam date. This is inherently good.
Second, there’s no way your retention is at all likely to be so low as to need to see all 6.3k cards every 4-5, or 8, weeks (will you need to know that H2O is water, for example? A silly example, but to drive home the point).
Third, by artificially capping your max interval so low the one thing you will accomplish is forcing Anki to show you a bunch of cards that you very likely don’t need to see and already remember. This will have the side-effect of significantly, and artificially, increasing and bloating your workload for a very, very minimal (if any) increase in actual retention. That’s a lot of extra work for very little, if any, benefit and very likely time that would be better spent on practice questions, developing silly mnemonics for the Krebs cycle, frolicking in the sun, etc. Low artificial caps to max interval don’t make Anki more effective; if anything, they make it less effective by increasing effort for little, if any, retention benefit.
This is kind of a long explanation, but hopefully it helps. The very, very short version is that this is, to be fair, a common misconception and it is an old debate within the Anki sphere and the overwhelming answer is that max intervals and exam dates are not related (and should not be).
By far the more recommended workflow is as follows:
Turn on FSRS and set your desired retention to whatever you want it to be. Say, 90%. Trust Anki to do what it’s designed to do; you’re going to remember 90% of your cards (adjust this up or down, if you want).
Before your exam, you might make some custom-filtered decks to specifically target certain subjects to refresh yourself on particular ideas, concepts, pathways, that you know you want to revisit before Test Day.
Let me know if this helps, if you have any other questions, and if there is anything else I can help with.
I see, thank you so much for the explanation. So what should I put my maximum interval to? Should I just put it to the default which is 36500 days?
I would set it to 1 year. I ended up settling on that myself, and it worked out well for me on the MCAT.
Let me know if you have any other questions.
Perfect, I just changed that. Could you also explain to me what the historical retention is? It is on 0.90 right now, should I keep it like that?
Historical retention, or desired retention?
Historical retention. I have my desired retention on 0.94 right now which is what I want. My historical is on 0.90 but not sure what that means. Is it something I should worry about?
Historical retention doesn’t really do anything. It’s really just there for modeling purposes. It’s mostly there in case you happen to know what your retention was historically, and want to compare it again future desired retention.
I touched it once, out of curiosity. It’s otherwise pointless, it doesn’t affect, or do, anything, and the devs are considering taking it out altogether bc it’s not really useful.