I had Skritter on fast adding mode up until a few days ago, and it was adding words at a truly prodigious rate - sometimes over 200 items in half an hour of study even though I still had a couple hundred reviews due.

Now I'm on normal adding mode, and it's only adding one word every couple minutes, even though I'm reviewing words at 94% due. I feel like fast was too much to maintain during the extreme challenge (especially for keeping myself supplied with new material and not being grossly overwhelmed when I slow down in a few weeks), but normal feels way too slow - I'll be studying words at 50% due by the end of the challenge given the current rate...

It is for the same reason I'm using manual adding in order to control my review workload.

I think adding words manually has worked better for me, too. If my queue isn't too big, I just add a few words at the beginning of my session, then I quit worrying about it. I've got it set to automatically add new words at "normal speed," but my queue is hardly ever at or near zero so it's essentially the same as manual only.

I'd be interested to hear whether others who have tried the fast adding also feel that it's too fast--it would be something easy for me to change.

I don't know that I would say that fast was TOO fast, necessarily - there's a place for its rate of vocabulary addition, and I was happy with it before I started the challenge, so I wouldn't say it's too fast, just that it feels like an untenable choice for me during the extreme challenge, since I would be swamping myself pretty quickly.

Yesterday I actually had a decent time with normal, since I added a bunch of words that I had no prior experience with (including quite a few unfamiliar characters in those new words), so I needed some heavy reps on them.

Really, though, the idea I'm going for is not that one's too fast or the other's too slow, but that there's an ocean between them.

I think fast is fine for when you want to clear a list, but I am finding normal a little slow. Not worth changing though, I'm sure the speed quite suits other's habits, and a little slow is better than a little fast.

Nick, are there numbers that can be assigned to quantify the different speeds? Or is it too complicated for that?

James

I find it too fast also; normal works for me. I don't like manually very much, because it's sometimes very slow, especially, when it goes through a list, where I already know a lot of words/characters, so Skritter has to search through the list.
What I would love to have is a field, where I could punch in e.g. "50" and then 50 items are added automatically, while I can still work further with studying, without having to wait for each and every item until it's added and I'm able to click for the next add.
If this would be available, I definitely would use this mode, as it would give me the best control in a very easy to use way.

I like Roland's idea about adding "x" number of words, although I'd probably never add 50 in one sitting. More like 5 or 10, but it's be nice to not have to tap the green "+" so many times.

And I also find "fast" a bit too fast, but I rarely use it.

James, there are always numbers. ;)

There's just a random chance whether to load a review or add a new item with each prompt. This probability is based on a quadratic function on the difference between the readiness of the most-due item and the add word frequency setting:

probability_of_adding = (1 - (readiness - add_frequency) / 0.4) ** 2

The available adding frequencies are given as:
.9: Fast
.7: Normal
.6: Slow

So if you are set to fast, then items will start adding (very infrequently) as you get below 130% (1.3) readiness, speeding up until you can't get below 90% readiness.

And if you are set to normal, then when you're at 100% readiness, roughly 6.25% of your reviews will be new.

Not the most finely tuned approach; I never had a good way to measure the effectiveness of various approaches. I have been meaning to add some more complicated heuristics, but haven't gotten to it yet.

My latest update on this note - I've gotten to a point in my queue where a lot of the words include one or more characters I don't know, and normal adding is about all I can handle in this situation. I was spoiled for a couple weeks with words that were almost purely made up of known characters, so normal seemed way too slow. Now it's much more reasonable.