We're the team behind Flips, a flashcard app built around the idea of showing you a word right before you forget it. Something we hear from learners all the time: “words I already know keep coming up, so I never get to the ones I'm actually weak on,” and “I want to drill just the words I get wrong, but I can't make that happen.”
This is a completely reasonable wish. Reviewing words you already know feels nice, but it does almost nothing for learning. The time you should really be spending goes to only the weak words — the ones you haven't learned yet or forget right away. In this article we'll lay out how to focus your study on weak words, and how to keep that going without strain.
Reviewing everything “equally” is the biggest waste
Flipping through a deck front to back, in order, is the usual approach — but it shows the words you're good at and the ones you struggle with the exact same number of times. You spend time on words you've already mastered while the weak ones stay buried in the pile, and you end up just short of learning them. The waste is that your study time is allocated in reverse of your mastery.
To strengthen memory efficiently, the sensible allocation is “space out the words you recalled, and bring back the ones you couldn't, sooner.” Words you know won't fade for a while even if left alone, but weak words fade fast, so they need to be recalled again at short intervals.
“Collecting” weak words by hand never lasts
So you'd just gather the words you get wrong and drill those — but trying to do it on paper gets tedious fast. You mark the missed words, stick on sticky notes, copy them into a weak-words list, and erase them once learned. It works at first, but as the words pile up, managing the list itself becomes the burden, and most people give up partway. And sticky notes can't tell you when you should see each weak word again, either.
In the end, most people fall back to “redo everything from the start,” and never get to study that targets only their weak words.
Let “weak-word detection” and “re-showing” run automatically
We built Flips because we wanted to automate exactly this — spotting weak words and cycling them back. In Flips, every time you answer, your mastery is recorded word by word. Words you miss or feel unsure about are judged “weak” and brought back sooner, at short intervals. Words you answer instantly get much longer intervals and stop appearing for a while.
You don't need to stick on notes or build a weak-words list. Just answer the words as they appear with “knew it / didn't,” and the system automatically shifts your study time toward the weak words. In Card Mode you swipe to mark knew/didn't know; in Quiz Mode you answer from four choices — either way, just answering updates the weak-word judgment behind the scenes.
As a result, your study time naturally concentrates on the words you're one step from learning. No wasted time on words you've got down; recall the fading weak ones just before they slip. That's the sweetest part of spaced repetition based on the forgetting curve. Decks for English, Spanish, Chinese and more are built in, and weak-word management works the same way in your own custom decks.
Focusing on just your weak words doesn't take strong willpower — it takes a system that picks up the weak ones and serves them to you automatically. Let Flips take over that tedious part for you.
Flips
The flashcard app that shows you words right before you forget them. Weak words are detected automatically and brought back sooner. Free to start.
Learn more about FlipsFrequently Asked Questions
Do I have to pick and tag my weak words myself?
No. Flips judges weak words automatically from your answers. Words you miss or feel unsure about come back at short intervals, while words you answer instantly get longer intervals. No need to make sticky notes or a weak-words list by hand.
Words I already know keep appearing and eating my time.
Words you keep getting right get longer intervals automatically and stop appearing for a while. Your study time naturally concentrates on the words you're one step from learning, so the ones you've mastered take up far less of it.
What if a weak word I'd learned goes shaky again?
If it gets shaky again, it's re-judged as “weak” at that point and shown again at short intervals. Mastery updates each time, so even with ups and downs, words come back at the right moment.
Does weak-word management work in my own decks?
Yes. In custom decks, mastery is recorded word by word just like in the built-in decks, and weak words are brought back sooner. The harder-to-learn items — exam terms, jargon — are where you'll feel it most.