FSRS: "Difficulty" During Learning Phase

Anki FSRS
1

Just a quick question regarding difficulty within FSRS. I was under the impression that difficulty didn’t change during the learning phase, although after searching it seems that’s the case with “ease” in SM-2, but not with difficulty in FSRS? I can also see that once difficulty is set, it doesn’t really drop by anything worthwhile unless you press “easy”; which is generally advised against.

So if I’m learning 20 new cards for the day, card 1 appears, I get it wrong since I haven’t learnt it yet (difficulty rises to 60%), Anki puts me through a number of the other 19 cards, I get back to card 1, and it hasn’t stuck (mostly due to the fact that I’ve only seen the card once and I’m also learning the other cards at the same time), I get it wrong again. My difficulty is now 89%, this kind of makes sense in the sense that it was somewhat difficult to pick up. But the card comes round a 3rd time, I get it right, and I get it right every time it reapears in future, but the difficulty will still be 80-89% and essentially will stay around that level, even when my interval 365+ days. For example, I have a card that is 71% difficulty and yet the interval is 7.5 months.

Therefore the only cards that won’t have a difficulty of more than 50% are cards that I already knew? Doesn’t this skew figures?

I know some people say you should learn the cards before using anki, but my issue with that is if I learn something then come to Anki, it’s already going to be present in my mind so I’m naturally going to get it right on Review 1, even though it’s not something that I knew already, which would skew my answers also.

My settings for reference:

Learning Steps: 1m 10m
Desired Retention: 90%
Params (optimised): 0.1538, 2.4454, 16.7204, 85.9914, 6.4194, 0.9003, 3.3123, 0.0048, 1.8844, 0.0358, 0.8148, 1.5295, 0.0258, 0.3120, 1.7637, 0.5355, 1.8729, 0.7373, 0.1361, 0.1897, 0.1000

2

This isn’t a response to FSRS or any complaints about the algorithm, as I haven’t looked into it.
I’ll just share a few of my thoughts, but it’s up to you to decide what to do.
So, you have 20 cards, but you need to figure out how many you study in 1 minute. It’s not just about hitting “Again,” but the time it takes to study each card. The thing is, ideally, this whole thing was designed for 10 cards; even when you’ve gone through them all, none of the cards are that far off, but when you’ve got 20, you start to forget them even more. I don’t set “1m 10m” but “30s 3m 10m” Even better, say, if I set a repeat before bed, it would be “30s 3m 15m 2h”
You could even set “30s 1m 5m 15m 2h” and not press the “Again” button right away.
The “30s” time is not just a random number, but rather a time that ensures the card appears three cards later, meaning it’s very close and you haven’t forgotten it yet.

1 Like
3

How much Difficulty (D) is adjusted, and under what circumstances, is based on your personally optimized parameters, so there’s no broad rule that “it doesn’t really drop by anything worthwhile.”

[But no – there’s no general advice against using the Easy button, as long as it’s the honest and accurate grade for the answer. If you’re using the buttons correctly, that will be rare.]

The primary reason for that isn’t the other cards – it’s usually that you aren’t doing what you need to learn the material. If you’ve decided to see new material for the first time in Anki, then you have to take the time then to learn it. If you get an answer wrong, what are you doing right then to make sure you have a better chance of getting it right the next time? If you just grade it again and hope for the best, you’ve skipped a step.

The second factor there is either the length of your learning steps, or the number of cards you have stacked up in Learn/Relearn at once.

This isn’t a problem though. You’re reacting to D as though it is some sort of value judgment or punishment – something that you should try to lower or that should always get better over time. But it’s just part of the memory state of a card that impacts how fast intervals grow. FSRS has looked at your review history and found that cards you have challenges learning need for their intervals to grow more slowly. That’s it.

1 Like