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How fast do the skills degrade?

I took shortcuts and tested out of many levels in French, just a week later many levels that were completed (gold) are not anymore.

that seems like extremely fast degradation and no easy way to restore them either (shortcuts not available anymore)

anybody knows how this works?

October 9, 2013



I believe new words and skills should degrade about the next day since they have been introduced for the first time, and then the degradation speed should depend on the correctness of the learner's answers.

The question is, should the tested out skills be considered new? People usually test out when they know the topic well and don't need to repeat it.

Anyway, the current skill decay system is, unfortunately, far from perfect. One has to apply common sense and repeat words/skills (s)he does not remember very well.

  • 116

Yes, I would hope that skills you've tested out of would be initialized with a lower decay rate, on the assumption that it's "old" or "stable" knowledge. So far this seems to be the case with my French skills.


It is interesting that you think they degrade fast. In my opinion they don't degrade fast enough at all. Especially new skills should be degrading much faster than they do


Franky -I have 15-18 skills decay per day in my German tree. Do you not think that is a but much? It feels like I'm spending all my time re-doing lessons on words I already know, instead of learning new vocabulary.

In contrast, my Spanish tree decays 2-4 skills per day.

Am I being A-B tested? If so, I'm not a fan. And I'm considering switching to a different language app.

What is the algorithm for for calculating if I may have forgotten a word? Because it doesn't feel like it's doing a good job.

  • 116

Interesting -- I tested out of a few levels in French five days ago, and they're all still gold. Maybe they'll start to degrade in a couple of days, or maybe they're being topped up incidentally by the new lessons I'm doing.

Anyway, skill degradation speed is not constant: when you learn something for the first time it will degrade quickly, but the decay gets slower with every successful review (google "spaced repetition" for more details). In my experience, timed practice of particular skills is the fastest way to "re-gold" stuff that you know well.

I think there are still a few bugs in Duolingo's decay system though. For example, the German genitives skill (which I think I can now complete in my sleep) seems to decay very quickly for me, while other things that I know less well remain on gold. The algorithm gets tweaked every now and again so things tend to get better with time.


In the past week I've had to strengthen objects and household everyday. I know them by heart and don't get any wrong yet they still degrade everyday. It's ridiculous, they need to sort that out. If you strengthen one lesson they shouldn't degrade for at least a week.


I agree with FrankySka, the words do not degrade as fast as they should. As to how to restore the "gold bars", I usually enter the topic and hit "Practice weakest words". I believe, that's the quickest way to address specifically the decayed vocabulary. On a related note, I have also noticed that when you practice one topic, some other topics get restored, as well.

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