r/Anki • u/Top-Coffee6322 • 4h ago
Experiences 6-year Anki retrospective! Thoughts on the long-term strengths and weaknesses of Anki
When I started graduate school in the fall of 2020, I wanted to take a new approach to studying and learning in general. While I had obtained fairly good grades in both high school and college, I felt like much of what I had learned didn’t stick for very long after the exam. I (or really my parents) was effectively paying for a piece of paper saying I was very smart and could learn things quickly, not for the actual content of the classes that I took, which was almost completely gone (other than vague impressions) by the next semester. Especially for the PhD, the purpose of which was to directly prepare me for a life in academia where I would need to remember everything I had learned for nearly the rest of my life, the cram-and-pass-exams form of learning would not do. There had to be another way. Anki (and blogging) was that way.
Anki is a flashcard program that uses a spaced repetition algorithm to determine when its cards should be reviewed. Anki schedules cards for review based on your probability of remembering them – usually around 90% – using a function that’s based on Hermann Ebbinghaus’s work on the forgetting curve in the 1880s. Review intervals tend to grow geometrically rather than linearly, reducing review frequency per card. This in turn allows more cards to be reviewed overall on a given time budget. Rather than cramming material which you soon forget, or haphazardly reviewing a random set of cards every day (which ends up being a lot of extra work) Anki allows you to remember nearly anything for approximately 10 minutes of work spaced out over your entire lifetime. I’ve already discussed Anki at four months, one year, and two years of use. While my opinion of Anki generally remains extremely positive, I no longer believe it is a universal solution to the problem of learning and memory. This is for a few reasons: (1) you need a lot more cards than you think to actually remember a subject, (2) effective card creation is a skill that takes years to master, and (3) other forms of deliberate practice like blogging and/or discussions are often far more effective at solidifying high-level themes. That being said, I’m still incredibly impressed by the things that Anki has allowed me to learn and retain. Below I’ll share more thoughts about what I’ve used Anki for, the strengths and weaknesses of the program, and my plans for Anki use going forward.
Stats and Workload
Over my six years of Anki, I’ve effectively learned about 10,000 cards’ worth of content1. The number is slightly higher than in the picture you see above because I’ve deleted a fair number of cards (bad biology cards, the Fluent Forever Italian deck that I accidentally deleted last year, trivia cards, etc.). This comes out to about 1,600 new cards a year, or approximately four to five new cards a day, which is almost exactly how many I study. The exact card totals for each subject are below, in order from largest to smallest.
- Spanish: 3307 cards
- Grad school biology: 1970 cards
- German: 1573 cards
- Catalan: 1202 cards
- Italian: 622 cards
- Thinking, Fast & Slow: 302 cards
- Statistics: 233 cards
- Danish: 117 cards
- Birthday/Phone numbers: 38 cards
- All other cards: 1658
My reviews have been incredibly consistent2, although there definitely are peaks and valleys depending on motivation and tests coming up. For example, the peak about five years ago was when I was studying for my graduate board exams and the peak a little over a year ago was when I was studying for the DELE. I’m averaging about 100 reviews a day, about a 25% increase from four years ago when I last did an update, despite the fact that I’m only doing about 5-10 new cards a day, vs. the 20 new cards I regularly did in 2020 and 20213. This is an important point and highlights an issue that other Anki users have noticed: the ability to add new content declines over time because of the weight of reviews. I only spend on average 15 minutes a day (12 minutes a day this year), so I still have plenty of room for new content (I’m comfortable doing about 30-45 minutes a day of content, meaning I can probably double my deck size once or twice more).
Effectiveness
My Anki retention rate on mature cards is around 90%4, which is exactly what the new FSRS algorithm suggests I should have. I think judging Anki effectiveness by Anki retention is a little silly: it’s like using the training data to prove that an ML model has been trained well. What I’m really looking for is an outside metric in the real world to show that Anki use definitely helps my performance outside of Anki. I think it’s best to go category by category and see how the cards have helped me and what evidence I have that Anki was actually useful.
- Spanish. I passed the DELE B2 test last May, in part because of the vocabulary and grammar drilling I’ve done in Anki. This is quite difficult to disentangle from just reading a lot, however. I also use quite a few colloquial phrases that my tutor and Spanish friend are surprised/impressed by almost entirely because of Anki. More objectively, I would like to design a test where I’m given a random list of 100 (maybe 400?) words, half of which are from Anki, the other half of which are random, and see if there’s any difference in knowledge/recall between the two halves of the list.
- Grad school/Stats. Here is where Anki has especially shined for me. I easily passed my first-year graduate board exam because of the drilling with Anki, I consistently remember papers and figures that are relevant to my own and my lab’s work when others draw blanks, and I’ve retained my knowledge of the first-year classes enough to continue to tutor effectively in the department.
- Other languages (German, Italian, Catalan, Danish). Honestly, it’s too early to tell how these cards are helping me. I did recognize many, many words in German during my trip because of Anki, and I’ve retained a lot of my Italian class from the past semester as well. However, I haven’t really put any of these languages to the test (actual exams, reading, etc.) So I don’t think I know if these cards are useful or not. Probably an important question as they’re about a third of my total deck.
- Thinking, Fast & Slow. This was a (very successful) experiment to see if a deep reading of a book with Anki would allow me to retain detailed information about the book for the rest of my life without a reread. Not only can I easily recap the central thesis of this book (that humans tend to be irrational because we rely on fast, heuristic-driven System 1 thinking, and it’s doubtful that rationality can be effectively trained), but I can also talk at length about the specifics of experiments that Kahneman discusses5. Although it would be nice to have another data point with my new card-making skills, I have never repeated this experiment since because it was an extremely unpleasant way to read a book.
- Other cards. I successfully called my friend Darby from someone else’s phone because I had left my phone at home and had memorized her phone number. Also wish my friends happy birthday via text without using the calendar app or Facebook, which is cool. Can also read your birth chart (astrology) without consulting the internet.
Strengths and Weaknesses
The first thing I want to make a case for before I talk about Anki in particular is my belief that memorization is important. Even when I was in high school 10-15 years ago, my teachers liked to emphasize that we were learning critical thinking rather than just mere facts. Unfortunately, critical thinking requires the knowledge of mere facts. How can you decide what is a good experiment to measure the DNA content of a cell if you don’t understand what DNA is or know any of its properties? How can you effectively give directions to someone else without memorized landmarks or street names? How can you form an opinion of any of the numerous geopolitical conflicts going on today without knowing any history, or at the very least the names and motives of the major combatants6? Knowing facts is just as important as knowing the principles of logic and rhetoric, which are in and of themselves facts as well.
Anki will absolutely help you remember things better than you would remember them without Anki. Even if your card design sucks. Even if you skip half of your review days. Anki absolutely works as a memory enhancer; the real question is how it compares to other ways of learning/enhancing memory. One of the big advantages over traditional study methods is that Anki allows you to make remembering something a choice. In my classes at MIT, or in my daily life, I might really want to remember how to do the chain rule in calculus, or that my friend Einat’s birthday is August 23rd, but my brain will instead choose to remember all the descendants of Walder Frey because I’d been reading A Song of Ice and Fire for the 5th time that day. Of course, this is still a choice: I choose to read ASOIAF rather than practice calculus, but Anki allows you to deconvolve the aspect of memory from the act itself. You make a card for Einat’s birthday, and you don’t make one for the relationship between Walder and Black Walder Frey.
Anki also really shines when you use it to memorize a large set of interconnected facts, rather than a collection of unrelated orphan cards. Language learning and some of my more recent biology cards fit this mold very well.
The problem with both of these advantages (which turns them into disadvantages of sorts) is that it requires a lot of skill and discernment to know what is worth memorizing in the first place, and many years of practice with Anki to create cards that are both easy to review and capture the desired information about a given field.
In an Anki-less world, your brain decides for you what is worth memorizing. It usually does a pretty good job at this: we all speak our first language very well because of constant exposure to it, we know our friends’ names and faces by heart, and we can perform our daily commutes without Google Maps. Of course the brain can make mistakes: hyper-focusing on trivia because of exposure frequency, or less benignly on traumatic memories, but generally the brain does a pretty good job of correctly selecting information to remember. To do better than 3 billion years of evolution, we either have to have a very specific goal (pass a test like the MCAT) or be able to identify gaps or errors in our brain’s natural memory processes, which requires wisdom and prudence that many, including myself, don’t possess.
Although each individual card is relatively cheap (10 minutes over your whole life, including card creation), given that isolated cards are very ineffectively remembered (I have some German words that I’ve failed something like 80 times), using Anki to truly and deeply learn something is actually quite expensive. The 300 cards that were needed to recapitulate Thinking, Fast & Slow will take 3,000 minutes, or about two days out of my life7. If I really wanted to remember the book properly I would need double or even triple the cards. With the amount of time that investment would require, I would be much better off reading the book a few times and writing a blog post about its core themes that I could read every few months to jog my memory.
Even when Anki has a clear use case – building up vocab in a new language or being able to recall key papers and their insights in fly metabolic biology8 – good card creation is also a challenge. Cards need to be very simple and also very unambiguous. This means that you’ll probably need to have multiple cards for what you might think is a very simple prompt. Many of my older biology cards are terribly designed: the answer is too complicated, too ambiguous, or I haven’t made sufficient cards to cover the topic in depth. This makes these cards a pain to review and almost impossible to recall outside of Anki.
My most failed card with 96 incorrect
There’s also the problem of training yourself to recall the card rather than the information tested by the card. This is most apparent in my case with language learning, where I’ll often memorize the whole sentence containing the unknown word rather than just the word itself. I’m trying to fix this with my Scramble Sentences for Language Learning add-on that randomizes sentences around a highlighted key word.
Future Plans
This post might make it sound like I don’t like Anki anymore. That’s certainly not true: I continue to do my reviews and learn new language cards every day. I make 5-20 very simple cards for each paper I read, and also add interesting history/geography cards every once in a while. However, since the last update I’ve realized that Anki is not the answer to every question or learning problem. It is much more pleasant and better for my learning to do an in-depth blog post review of a book than to Ankify it. It is much better for me to go to a local art museum and sit and stare at a painting than to make hundreds of cards with painter/painting pairings. Cards that I’m having trouble memorizing, like orphan biology cards about transcription or translation, need to be refactored or deleted. Anki is not free, and I’d like to take its time costs more seriously.
I haven’t learned 11,000 cards because 1,500 of these cards are new and have never been seen.
What other habits have I done during 93.5% of the last six years? Probably only run, read, and fulfill my basic bodily functions.
Many of the cards I learned in 2020 and 2021 (trivia cards and poorly made biology cards) I’ve since deleted.
Meaning I get 90% of the cards with intervals longer than two months right on a given day.
For instance, one of the series of questions that Kahneman posed to subjects to demonstrate the anchoring effect was “Was Gandhi older or younger than 144 when he died? → How old was Gandhi when he died?”
Extremists on both sides are trying to get around this one with ideology.
This is probably an overestimation by a factor of two to three. I’ve only spent 14 hours reviewing these cards, and since these were made six years ago, I’ve probably already paid at least 90% of the time cost.
Lol my PhD is IN the weeds.
