What is Dorothy?

Dorothy is a study tool for the long-term learner.

Whether you’re learning a new language, preparing for a large exam, or working on a certification, Dorothy will ensure you spend as little time as possible studying what you already know and more time focusing on what you’re about to forget.

What are people using Dorothy for?

A project manager from Guadalajara is using it to study for her PMP exam.
A student from Russia who recently migrated to Israel is using it to learn Hebrew.
A programmer from the United States is using it to master his Spanish vocabulary.

And much more. If you’re learning something and want to remember it for the long term, with minimal time and effort, then Dorothy is for you.

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Available on all devices

Use Dorothy on whichever device works best for you. Whether that’s desktop, tablet, or mobile, Dorothy will help you retain anything you’re studying in the most effective and efficient way possible.
Take the passive approach

You’ll never have to plan your schedule or set aside time to study with Dorothy. We’ll send you a notification when your quizzes are ready. Just answer the questions and you’ll learn automatically.
Deeper cognitive processing

Memorize faster and form stronger neural connections using active recall. Dorothy predicts, to the day, when you’ll forget an answer and quizzes you the day before to keep it in your memory.

About Dorothy

How it works

Dorothy can be used to add anything to your long-term memory in 4 simple steps:

1. Learn something

Whether you’re studying for class, preparing for a grad school exam, or learning a new language, Dorothy is prepared to help you remember anything.

For example, let’s say you’re studying Spanish. You learn that the word for “cat” is “gato” and you want to remember that forever. All you have to do is open up your phone and enter it into Dorothy.

2. Add it to Dorothy

Open Dorothy and rephrase that information into a question. In the case of “gato” it would look like this:

Question: What is the Spanish word for cat?

Answer: Gato

Hit save and put your phone down. Dorothy will take care of everything else.

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Hint: you can also use our Chrome extension to automatically generate questions using AI.

3. Answer your quizzes

Within the next couple days, you’ll receive a notification that you have a quiz due. Open up Dorothy and take your quiz.

You’ll be asked: What is the Spanish word for cat?

There will be a timer counting down to keep you focused. Once you think you remember the answer, click the reveal button and you’ll see the answer: Gato

You will then be asked if you recalled the correct answer. You’ll choose one of the four following answers: Yes and it was easy, Yes and it was hard, Almost, or No.

4. Let Dorothy do its thing

This information will be added to the spaced repetition algorithms and used to increase the accuracy of your learning system.

Over the following weeks, Dorothy will wait the appropriate amount of time to quiz you again. By increasing the intervals of time between quizzes and only quizzing you right as you’re about to forget the answer, the answer will be embedded in your long-term memory and you’ll never forget it.

You can put as many questions and answers as you want into Dorothy, and each one will have its own custom interval system, so you’ll be able to continue learning as much as you want.

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Why Dorothy works better than any other memorization tool out there

Dorothy uses spaced repetition a research-backed learning technique that increases your ability to memorize, remember, and recall anything.
Your brain uses active recall resulting in a deeper level of cognitive processing than passive recall techniques such as reading notes or flashcards.
Dorothy does the work for you. Dorothy is designed to be quick, easy, and enjoyable. All you have to do is add questions and answer quizzes and you’ll memorize them automatically.
Dorothy’s spaced repetition algorithms are constantly being updated depending on your input. The more you use it, the more accurate it becomes.

Features

On mobile, tell us whether you recalled the correct answer in the quiz

Simple UXSo easy anyone can use it.
Self AssessmentUpdates your algorithms daily.
Passive LearningYou never have to plan your study schedule. Just hit next, and we'll do it for you.

The Nitty Gritty

How it works on a more technical level

Dorothy’s formulas are continuously being updated and customized based on user input.

Every question in Dorothy has its own multiplier. That multiplier is used as a variable to help determine when the next time the quiz will be due. Every night Dorothy makes minor adjustments to the multipliers of all questions.

For example, Dorothy quizzes you and asks “What is the Spanish word for cat?”

You think to yourself “Oh, I know it! It’s… cato? No. It’s gado. No…” but time runs out.

When it does, Dorothy asks you “did you recall the correct answer?” You were close but you didn’t quite get it, so you click “Almost”.

Once you’ve self-assessed how you’ve done, Dorothy will then determine when you need to be quizzed on this question again.

This is an example of a formula Dorothy uses to determine the number of days until the next time this question is asked when the user answers “Almost”:

Ddiff-almost = (2 - 1/(Nattempts^(1/3)))^(1/1.1) * (Ddays * Mcurrent)^(1/2.5)

We divide 1 by the cube root of the number of times this question has been quizzed, subtract that from 2, then raise it to the (1/1.1) power. We then multiply that number by this number: the number of days in the last interval times the current multiplier of that question all raised to the (1/2.5) power.

The end result of this equation is the number of days until this question comes up in a quiz again. So if you took the quiz on December 1st and the result of the equation is rounded down to 4, then we’ll ask “What is the Spanish word for cat?” again on December 5th.

Note: this is just an example of a formula that may be used. These formulas get continuously updated and customized based on the feedback of our system. This may be used for one question for one quiz at one time, but the next time may use a totally different formula. This is part of what sets Dorothy apart from the pack: every question’s intervals are customized based on the user, the question, the question’s history, and continuously-updated formulas. And the best part, it gets more and more accurate the more you use it!