By Scott Kobner

Medical Student
New York University School of Medicine


Disclaimer: The following post is about an educational product, I have no financial interest or stake in the success of Anki and no conflicts of interest to disclose. I have used several flashcard applications, and the following represents my opinion as a poor medical student.


If you’ve been following the blog, you are probably eager to sink your mental teeth into the spaced repetition learning Salim Rezaie described in his recent post. Though spaced repetition may just now be making its way into the mainstream of medical education, medical learners have been utilizing this practice for several years as a practical means of taming the exponentially growing fund of undergraduate medical knowledge. For many medical students, one tool has long stood out among the rest, becoming an essential resource for modern medical education.

Anki (pronounced ank-ee) is an incredibly robust, open source, flash card application that utilizes active recall testing paired with a spaced repetition learning algorithm. This algorithm, known as SM2, was born from educational research in the 1990s, which ultimately lead to the world’s first commercially successful spaced repetition software entitled SuperMemo. While the creators of Anki have made some adjustments to this algorithm for both technical and pragmatic reasons–as discussed extensively in their documentation–the fundamental idea remains the same:

Anki asks users to recall information and users rate how difficult it was to respond. User difficulty ratings are then used to determine the ideal time to challenge the user with that information again in order to maximize long term retention.

By keeping track of how well you remember things, Anki models your memory decay over time. Before you ever realize the name of that obscure long QT syndrome associated with severe, bilateral sensorineural hearing loss is fading from your memory, Anki will prompt you to remember that it is Jervell and Lange-Nielsen syndrome.

Getting Started With Anki

The desktop version of Anki can be downloaded for free, but the mobile application will set you back $24.99. The free dekstop application will suit most users needs, but for those serious about taking their learning on the go the steep price for the app will feel like money well spent.

It’s best to watch some of the tutorial videos found on the Anki website to familiarize yourself with Anki’s interface before getting started. New users will notice that the program is centered on the familiar concept of “cards” stored in “decks.” Each card is meant to represent one concept or fact that you are trying to learn and decks represent very broad thematic groups for cards. Studying “decks” of cards is the simplest way to study with Anki, but it is probably most helpful to think of “decks” as a place to store your cards rather than subject areas you are trying to learn. In Anki, separate decks are best utilized for entirely disparate subject matter, as opposed to topics users are trying to master. Cards can be individually tagged within decks so that all of the cards on specific topic can be easily located, but Anki works best if topic interweaving is left to its own algorithm.

Making Cards In Anki

Anki is not a magic cure for long term retention, and it’s effectiveness is limited by the quality of the cards users make. Cards can contain standard text, specialized fill-in-the-blanks known as cloze deletions, custom visual cues, audio files, and even videos if you feel so inclined. Because it is open-source, Anki also supports countless community sponsored add-ons which continue to offer new features, such as in-app image occlusion for converting diagrams to cards.

There is an art and a science to creating effective flashcards, mastery of which is outside the scope of this post. One of the original creators of spaced-learning algorithms has written a seminal introduction to this skill. It is a must-read article that outlines twenty rules for formatting information in order to maximize flashcard-based learning. Try putting these principles to use when making your own cards to ensure that you’ll find Anki useful for years to come.

The task of creating cards can be time consuming, and so the Anki community has responded by supporting deck sharing, which enables you to build useful content with a group of collaborators. As an example, a reddit user on the medical school subreddit created a deck containing nearly all of the information needed for students to ace the USMLE Step 1 exam, and it continues to be an example of one of the most shared, highest quality medical decks of all time.

Using Anki Daily

In the past, you may have created flashcards in preparation for a big test, only to have your box of cards work their way to a distant shelf (or even into the trash can) after the exam has passed. But if you approach your use of Anki in this way, you’ll find yourself frustrated, overwhelmed, and unsatisfied.

Anki was designed to be used everyday. Cards that you answer correctly get moved from a “new” pile to a “review” list, only to be seen again when the spaced-learning algorithm determines your memory needs to be jogged with that information. If you only log in to Anki on occasion, you will let these memories decay and foil the entire system.

As you might imagine, this system allows cards to build up in queues for you to review. Of course, the number of cards you see everyday can be customized to fit your study time, but it can be intimidating to be confronted with hundreds of cards to go through daily. The value of the system soon becomes apparent when you begin recalling facts that you never realized you remembered.

Tracking Progress

For those who enjoy hard data, Anki has a robust user dashboard that allows you to track your progress over time. Information about how you’re progressing through a deck, your recall rates of individual cards, and even predictions about when you will forget certain cards can all be accessed through within the app or exported to another program for further analysis.

Anki Drawbacks

Though spaced repetition learning with Anki is a powerful tool, it represents only part of the medical educator’s arsenal. Anki will help learners recall thousands of facts, but it does little to help students master concepts. Without a solid understanding of the fundamentals of a topic, Anki is nothing more than a brute force memorization tool.

New users may also be uncomfortable changing their time-tested learning habits and incorporate Anki into their daily routine. It is a brave departure from traditional approaches; the daily, concentrated effort can feel grueling and mentally exhausting.  The time requirements to make effective Anki cards may also be a deterrent to some users.

Finally, Anki might not be suited for all learning styles. Those who seem to gravitate towards auditory and kinesthetic learning modalities may find Anki leaves something to be desired. Constantly thumbing through flashcards can feel monotonous, especially when the rewards are not immediately tangible.

Final Thoughts

Though I’ve been a regular Anki user for the past four years, I still have much to learn with respect to spaced repetition learning. Having said that, here’s my take: for a free, open-source desktop application, Anki is an extraordinarily powerful tool that can help tame the endless sea of medical knowledge learners are expected to acquire. It’s certainly worth a try if lifelong knowledge retention is a serious goal of yours. It may just reshape the way you learn – it has for me.




One thought on “Anki: The Ultimate Spaced Repetition Tool

  1. Jeff Riddell says:

    Wonderful overview, thanks Scott!

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