How is the score calculated in SRS?

kirkyonyx

Member
Hi,

I'm wondering how the SRS system by Pleco works. So I've tried to read the documentation but I couldn't find the math behind the scoring system in learning my flashcards in the Pleco Built-in SRS system with the default settings. What happens with the score when I tap "didn't know" for example?
Would be glad if someone here could help me out! :)
 

Shun

状元
Hi kirkyonyx,

The basic principle you need to understand is that the score increases if you gave a correct answer, and decreases if you've given an incorrect answer, and that the amount of this increase/decrease is determined by the easiness of a flashcard, which is a number saved with the flashcard along with the score. You get an idea of how easiness works on this page in the manual:

3D3A0D3D-A543-405D-B2D7-605E94882470.png

As you can read in other places in the Flashcards reference in the manual, you can fine-tune a lot of things around scoring. If you tap "didn't know" or "incorrect answer", the score will probably go down if you haven't already been tested on the same card that day. Pleco 4's system will be radically different, but it will come with a full Pleco 3 compatibility mode, as Mike has stated.

Hope this satisfies your curiosity to some extent, :)

Shun
 

kirkyonyx

Member
Hi Shun,

thank you for your answer! That describes the general approach pretty good, but I'm interested in how the score value is changed when I tap "didn't know", you know? ;) I know that I can modify the perccentage increase/decrease depending on the classification, but how is this solved by default?
 

Shun

状元
Hi kirkyonyx,

you're welcome. The default values for the change of easiness are just a reasonable number. How it happens is always more or less the same, i.e. through the same formula. :) I created a new profile which has the default settings, and it says there that the easiness will change by -10 if you give an incorrect answer, and by +4 if your answer was correct.

It seems to me that there are two main paths: If you have Prompt for quality enabled, the easiness changes in one of six ways you can set under Tweak Parameters (which depend on your answer in a test, how well you knew the card from 1-6). If you have Prompt for quality disabled, which is the default way, there are only the two values above you can set under Tweak Parameters for the easiness to change, one of which would be for the "didn't know" you mentioned. How the easiness affects the score change is influenced by the easiness divisor, which works like this:

Easiness divisor is used in the formula for calculating a new card score after a correct answer. The card’s easiness factor (which defaults to 100) is divided by this amount, then multiplied by the card’s score to get the new card score. This is an easy way to quickly make the algorithm more aggressive (by lowering this value) or less aggressive (by raising it) in how quickly it increases cards’ scores.”

Pretty simple, isn't it? :)

(I know it's tricky to get one's point across over the forums without the ability to ask back and forth easily.)

Hope this helps, otherwise someone else can add to this.

Shun


PS: To be sure, I don't fully understand the current Pleco 3.2 scoring system. I prefer manual control, and I think Pleco 4's system is the one I will look at more fully. I just thought you might be happy with my level of knowledge regarding Pleco 3.2's system.
 
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mikelove

皇帝
Staff member
I know that I can modify the perccentage increase/decrease depending on the classification, but how is this solved by default?
The default behavior in this case is that the score goes back to its minimum value of 100. (= 1 day SRS interval)
 
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