Why do some skills' strength go down faster than others?
This is really annoying to me. For example, I could strengthen a skill only to have it go down the next day while other skills stay gold for days or even weeks! Does this happen to anyone else?
The strength of skills is based on the strength of individuals words which are introduced in the skill. The strength of these words is reduced over time, if you get them wrong, if you peek at the translation by hovering over the word (but not the first time the word is introduced). I think it also considers the time you take to translate the word/sentence, and possibly a few other parameters as well. No one knows the full algorythm used and I am sure they tinker with it testing different ideas to improve its effectiveness.
Have Duo staff said somewhere that peeking when a word is introduced doesn't have any negative effect on strength? If someone had previous familiarity with a language, for example, and they didn't have to peek even the first time a word appeared, I would have assumed that would provide useful information Duo in principle would want to consider.
I am surprised that Duo would set a up a system where someone who for whatever reason already knew the words being introduced in a skill would experience the same decay rate as someone who did not. But Duo is clearly heavily slanted toward the absolute beginner, so I probably shouldn't have been.
I had always assumed the highlighting was something like a simple direction marker, making it clear you were learning something new for your trouble.
It depends if you find it easy on 1 of the sections it will go down slower! If you find it hard on a different section and struggle to get it strengthened but manage it will go down quickly! By the way you're not the only 1 as everyday now I try to keep them all strengthened but I've got too many so I just can't cope!
A skill shows at full strength whether the words therein are just a little over the minimum threshold or a long way over the minimum threshold. So in the former case, they'll degild a lot more frequently.
The very basic skills stay gold in part because they contain words that appear over and over throughout the course, so they're getting refreshed all the time by default. Other skills have much more specific vocab that might only appear in that skill.