Pick the weakest to strengthen.
When "Strengthen skills" button clicked, why not choose the most forgot one, i.e. the lowest strength one in the tree, to practice?
-- If I lose progress of one language for a time, when pick up, the button will chose one that most likely is familiar for me to practice, not efficient imho.
Duolingo's algorithms don't actually directly keep track of how strong a skill is. They keep track of the strength of individual words. The Strengthen Skills lesson is made up of whichever words Duolingo thinks you most need to see right now. Often those will be individual words that have weakened while the rest of the skill still shows as golden.
There's some more detail about how Duolingo keeps track of our learning here: http://making.duolingo.com/how-we-learn-how-you-learn
I beg to differ. I've been thinking about this when or after my studying via Duo in the past month. It's a good system, of course. But the revise picker is not good for everyone or every instance.
For example: Someone who revise once in a while but got familiar with the language by other means, the practice will always pick the relatively easiest for him. (Just the situation for my 3rd 4th languages etc.) And one may need interleaving, yet the Practice button won't provide it.
And let's think about the system again, Its game like interface made it easy to guess right answer, thus the curve is not that accurate to represent ones progress, just like the Fluency percentage cannot represent my really language skills.
Anyway, thank you, Duolingo. Wish you better and better still.
Yup, the system's good, but it isn't perfect. When it's working at it's best, it presents us with exactly what we need to see, but sometimes a question is only useful because of what Duolingo learns about us. ...and yes, it particularly can't know what you revised through other means.
Duolingo is a tool for the first stage of learning a language. By the time you're doing a lot of work elsewhere, it's probably time to move on.
I agree and use the 3rd party skill strength viewer. It gives you a percentage of strength for each skill from 0% to 100%. This makes it very easy to determine which skills need practice most.