# Why does reviewing ahead give the same interval twice? (FSRS)

**URL:** <https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272>\
**Category:** FSRS\
**Created:** [January 6, 2024, 2:29am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272 "2024-01-06T02:29:12Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![tomash95](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/tomash95/32/9335_2.png) [@tomash95](https://forums.ankiweb.net/u/tomash95)\
**Post date:** [January 6, 2024, 2:29am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/1 "2024-01-06T02:29:12Z")

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I understand that if you review ahead cards soon after they’ve been scheduled then it has little effect on new intervals because the scheduler can’t guarantee you know them well enough. But take this case:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/anki2/original/3X/9/1/9191240c11a39acb8ea4e30d406db02457c455f2.png)

I failed the first review when learning, then got it correct again 2 minutes later, so it was given an interval of a day. Five hours later, I created a filtered deck for two days worth of future cards to try and lower my workload. This card was then given an interval of two days. However, reviewing it today, it’s still given an interval of 2 days again. Is this intended? According to another similar card:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/anki2/original/3X/4/d/4d29be706c762435a777e07f30d5ca636b6ad544.png)

If I “good” a 2 day interval card, it moves on to 4 days. So, I would’ve expected the interval to grow at least a little more (3+ days), no? As a result, today and tomorrow I will have more cards to review than I would’ve had I not reviewed ahead. That doesn’t really make sense to me, but I might be missing something …

E: These are my weights:

`0.2006, 0.2006, 1.5137, 1.5137, 5.2518, 1.1796, 0.7372, 0.0547, 1.4611, 0.1383, 0.8329, 2.2442, 0.0818, 0.4163, 1.5125, 0.0281, 3.1448`

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**Author:** ![dae](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/dae/32/65_2.png) [@dae](https://forums.ankiweb.net/u/dae)\
**Post date:** [January 8, 2024, 12:25am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/2 "2024-01-08T00:25:15Z")

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@L.M.Sherlock any thoughts?

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**Author:** ![L.M.Sherlock](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/l.m.sherlock/32/16770_2.png) [@L.M.Sherlock](https://forums.ankiweb.net/u/L.M.Sherlock)\
**Post date:** [January 8, 2024, 1:51am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/3 "2024-01-08T01:51:11Z")

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![image](https://us1.discourse-cdn.com/flex002/uploads/anki2/original/3X/1/b/1bee31b9cbdbc9927d0c89bf4da09985fa4330b2.png)

This review was done in the same day, so it doesn’t affect the card’s memory state.

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**Author:** ![tomash95](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/tomash95/32/9335_2.png) [@tomash95](https://forums.ankiweb.net/u/tomash95)\
**Post date:** [January 8, 2024, 2:36am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/4 "2024-01-08T02:36:55Z")

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I’m confused. If its memory state was unaffected, why did its interval go from 1 to 2 days?

I think I also noticed something else. With 23.12 I retrained my weights as recommended, so all of my cards have a manual review. Take my history for the Japanese word 授ける (I’m not even sure why this card was included in the filter because it was only for 2 days ahead):

 ![image](https://us1.discourse-cdn.com/flex002/uploads/anki2/original/3X/0/6/06dce3af156c93707efdc6af6ff1db989f3220dd.png)

It looks like FSRS thinks I know this card well, but it shrunk my interval with the filtered deck. I think in this case the review being close to the manual rescheduling might be responsible? Either way, I think that its interval should’ve grown since I reviewed the card as good having not seen it since November.

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**Author:** ![L.M.Sherlock](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/l.m.sherlock/32/16770_2.png) [@L.M.Sherlock](https://forums.ankiweb.net/u/L.M.Sherlock)\
**Post date:** [January 8, 2024, 2:50am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/5 "2024-01-08T02:50:22Z")

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> [@tomash95](#):
>
> I’m confused. If its memory state was unaffected, why did its interval go from 1 to 2 days?

Perhaps it is caused by fuzz.

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**Author:** ![dae](https://sea2.discourse-cdn.com/flex002/user_avatar/forums.ankiweb.net/dae/32/65_2.png) [@dae](https://forums.ankiweb.net/u/dae)\
**Post date:** [January 8, 2024, 3:33am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/6 "2024-01-08T03:33:42Z")

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> [@L.M.Sherlock](#):
>
> Perhaps it is caused by fuzz.

No fuzz is applied to intervals \< 2.5 days, so that wouldn’t explain this case.

> [@tomash95](#):
>
> It looks like FSRS thinks I know this card well, but it shrunk my interval with the filtered deck.

It may not be related to the filtered deck at all. There are multiple other factors that may have influenced the resulting interval: the upgrade to FSRS 4.5, newly-optimized weights, a change in your desired retention, and scheduling fuzz.

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**Author:** ![system](https://us1.discourse-cdn.com/flex002/uploads/anki2/original/1X/8f1279ababc5879d54e4838989f606cfe55af8c7.jpeg) [@system](https://forums.ankiweb.net/u/system)\
**Post date:** [February 7, 2024, 3:34am UTC](https://forums.ankiweb.net/t/why-does-reviewing-ahead-give-the-same-interval-twice-fsrs/39272/7 "2024-02-07T03:34:24Z")

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