We try to avoid it, but sometimes there are situations where we need to add some "filler" to your list practice. Here's why:
- Your list does not contain enough words. If your list is shorter than 10 words, we'll need to add filler because we give questions in a series of 10 per round, and we never show the same word twice in a round.
- Your list does not contain enough "learnable" words. Similar to the previous point, if your word list does not contain 10 "learnable" words, we'll have to add filler. Read more: What makes a word "learnable"?
- We need to put some words on "hold" for a bit. Sometimes, if you've answered a lot of questions on the same word in too short a time, we decide we need to put them on "hold" for a little while (so that you have a chance to forget) and hold off on future questions on that word. If that happens, it's typically because you've gotten a bunch of questions right in a row on that word — so a little break won't hurt. If enough words on your list slip into this category, we might need to add some filler to beef-up your round.
We try to use 100% grade-A filler...
When we do use filler, we do our best to test you on other high-priority words you are learning.
Read more: Managing the Words in Your Learning Program