In my account settings I have set a target retention rate of 95%. But my real retention rate tends to be around 90-91% or so. Why is this? I thought that the words would be repeated until the target retention rate was reached, but after a while during practice I every day get words which are less than 100% due.

The program still adds new characters every now and then. Is there something I can do to increase my real retention rate? Or am I just a slow learner?

in order to get a high retention rate yu have to review your items more often, so you could increase this rate if you add words less frequent. (you can set word frequency in your account settings).

I never really care about this rate, mine is allways about 85 - 89%, because i dont want to review my items over and over and over again, this is boring.
i like to have new items added pretty early.

The retention estimations aren't super accurate, because a lot of reviews are at a short interval where the normal retention mechanics haven't really kicked in yet, and those have more weight than would be ideal. It works pretty well, but not perfectly.

90-91% retention is pretty fly, so I wouldn't worry about it. It's actually slightly more efficient to learn at that rate than 95%; it's just that 95% is usually more psychologically satisfying. If you aren't frustrated by how many prompts you get wrong, then you're golden.

OK, thanks.
I guess that this figure will get more accurate the more words you learn then, and the longer period Skritter is used for studying.
Excellent site by the way! Quite addicting too...

Thanks! You know I want you hooked. Maybe not as much as 穆儿, though.