Anki Algorithm Explained: How Spaced Repetition Works

You know how sometimes you study for a test and then forget everything a week later? Not anymore.
Introducing Anki, your rescuer! It isn’t just a regular study tool; it’s like a smart study buddy on your computer. Think of it as a special program that uses some clever tricks to help you remember stuff better.

What is Anki Algorithm?

Anki is an open-source computer program that uses spaced repetition to help people remember and learn information more efficiently. Though Anki isn’t an algorithm by itself, it uses multiple algorithms and methods to decide the best times and frequencies for reviewing flashcards, ensuring better long-term memory retention. Here, flashcards refer to digital cards that contain questions on one side and answers on the other. The primary purpose of these flashcards is to facilitate the process of spaced repetition learning.

How can Anki be helpful?

What? Can you learn with Anki? Almost anything!

Whether you’re trying to learn a new language, preparing for medical or law exams, remembering all the world’s capital cities, or even just trying to remember the names of all your classmates, Anki is there to help you out.
In simple terms, Anki helps you study smartly and remember things easily and is available on various platforms, including desktop computers, smartphones, and tablets.

Diving into How Anki Works

Anki is like a super-smart flashcard program that many people love. It has a special system that, when you review flashcards, helps you remember things better and for a longer time. So, Anki figures out the perfect time to show you those cards again to make sure you really remember them.

Let’s explore how the Anki Algorithm works:
  • Initial Learning: When you make a new flashcard or start studying a deck in Anki, you’re in the “learning phase.” During this time, Anki shows you these cards more often to help you grasp the material.
  • Review Time: Once you’ve gone through the initial learning, Anki switches gears to the “review stage.” Here, you get to rate how well you remember each card with options like ‘easy,’ ‘good,’ or ‘again.’ Depending on your rating, Anki decides when you’ll see that card again.

    Again: You didn’t remember the information or got it wrong.

    Good: You remembered it but with some difficulty.

    Easy: You remembered it effortlessly.

  • Timing Matters: Anki’s real strength lies in its timing. It figures out the best moments to show you a card again, aiming right before you’re about to forget it. This way, your memory gets a little nudged just when it needs it.
  • Ease Does Count: There’s something called the ‘ease factor’ in Anki. Think of it as a way to adjust how fast or slow you’ll see a card again based on how well you remembered it last time. It’s like fine-tuning your study experience.
  • The Algorithm: Anki uses a clever system, somewhat based on the trusted SuperMemo 2 method, to decide when to show you cards next. This system looks at how you did with a card before and calculates the best time for your next review. In simple terms, it’s trying to figure out the perfect moment for you to see each card again.
  • Inspired by the Leitner Method: Anki’s clever system takes a page from the Leitner System. Imagine sorting flashcards into different boxes. When you get a card right, it moves up a box. If you struggle with a card, it goes down a box. This way, Anki focuses on the cards you find challenging.
  • How Anki Figures Out Timing: Anki uses a neat formula to decide when you’ll see a card next. It’s like a math equation:
    Next time you see a card = last time * ease.
    This ‘ease’ is influenced by how you felt when trying to remember that card.
  • When You Forget – Lapses: If you ever can’t remember a card during a review, Anki sees it as a ‘lapse.’ That card goes back to square one, giving you another shot at learning it.
  • Moving Up with Graduating Cards: Cards you remember well get more spaced out over time. This means you see them less often but still remember them. Anki tweaks timings and intervals to help you remember these cards for the long haul.
  • Your Daily Flashcard List: Every day, Anki lines up flashcards you need to review. This list mixes new cards with ones you’ve seen before, all based on when you last saw them and how well you remembered.
  • Customization: Anki isn’t one-size-fits-all. You can tweak settings like how many new cards you want daily or how often you review. This lets you adjust Anki to match your unique learning style and goals.

Mastering LinkedIn with Anki: Boosting Your Professional Network

LinkedIn is where professionals connect, share knowledge, and grow careers. But what if you could supercharge your LinkedIn experience with Anki, a smart flashcard program?
Here’s how blending Anki’s power with LinkedIn can make your networking game stronger:
  • Turning Connections into Flashcards: Think of every person you connect with on LinkedIn as a flashcard in Anki. On these cards, jot down key info like their name, job title, company, and any standout moments or chats you’ve had with them.
  • Ranking Your Chats: Sort your interactions by importance or type. Maybe you’ve had a casual chat with someone, or maybe it was a serious business talk. Label these chats so you know their significance later on.
  • Diving Deeper into Interactions: Make your flashcards richer by noting specific details. Did you talk about a recent project? Note that. Did you meet last month? Mark the date. These details help jog your memory about past conversations.
  • Rating Connection Importance: Give each connection a ‘rating’ based on how crucial they are to you professionally. Those vital connections? Assign them a higher rating. This ensures you revisit and remember them more often.
  • Adjusting Your Study Schedule: Use Anki’s smarts to decide when to review each connection. By tweaking settings, you can make sure you’re focusing on the most important connections more frequently.
  • Keeping Your Connections Fresh: Regularly go through your flashcards to refresh your memory about key LinkedIn connections.
  • Customizing for LinkedIn Goals: Tweak Anki settings to suit your LinkedIn goals. Want to focus on industry-specific chats? Done. Do you need to remember people from certain companies? Adjust the settings. Tailoring Anki this way ensures it aligns perfectly with your LinkedIn strategy.

Example: Create a Flashcard for John Doe in Anki:

Card Front (What you’ll see)
  • Question/Title: John Doe – Senior Software Engineer at XYZ Corp
Card Back (Detailed Information)
  • Name: John Doe
  • Position: Senior Software Engineer
  • Company: XYZ Corp
  • Interaction Type: Casual
  • Last Interaction: 2 weeks ago
  • Discussion Points: Discussed the latest software development trends.
  • Priority: High

Understanding Priority Scores for LinkedIn Connections

Imagine you want to figure out how important it is for you to keep in touch with someone on LinkedIn. Let’s break down how you can calculate this importance using a simple formula.

1. Types of Chats Matter:

Every chat or meeting you have can be a quick catch-up, a fun social chat, or a formal business talk. We give different “scores” to these types to show how important they are:

  • Quick catch-ups (Casual): Considered somewhat important, gets a score of 0.5.
  • Social chats: A bit less important, so they get a 0.3 score.
  • Business meetings (Formal): Least frequent, hence least score at 0.2.

Example: You had a casual chat with someone recently, so it’s marked as 0.5.

2. When Did You Last Chat?:

How long ago was your last chat or interaction with this person? If it was just yesterday, it should count for more than if it was a month ago.

Example: You chatted with this person 10 days back.

3. Giving Recent Chats Extra Weight:

We want to emphasize chats from the recent past. So, we boost the importance of recent chats using a special math trick. It makes recent chats count even more.

Math Trick: The formula given is: Weighted Days Since Last interaction=Math.pow(daysSinceLastInteraction + 1, 1.5)

Given daysSinceLastInteraction=10days

First, add 1 to 10: 10+1=11

Next, raise 11 to the power of 1.5: Math.pow(11, 1.5) =34.52

Example: Your recent chat’s boosted score is approximately 34.52.

4. Calculating the Overall Importance:

Finally, to get the total importance or “priority score”, we mix both the type of chat score and the recent chat boost.

Math Done: You multiply the type of score (0.5) with the boosted recent chat score (34.52). And that gives you a total priority score, which is roughly 17.26.

By combining how important a chat type is with how recent it was, we get a score that tells us how vital it is for you to keep that LinkedIn connection active. The higher the score, the more crucial it is for you to stay in touch!

Case Studies

1. Anki’s Impact on Medical Students’ Exam Performance: A Quick Look Study Overview: Source: In 2015, a research team wanted to see how well medical students did on their big U.S. medical exam (USMLE Step 1) based on their study habits. They focused on students from Washington University School of Medicine who had just finished their first two years of study. The Tools They Used:
  • Anki: A digital flashcard tool that uses a method called spaced repetition. This means it shows you cards more often if you don’t know them well, helping you remember better.
  • Firecracker: Another flashcard tool designed especially for the USMLE Step 1 exam.
What Did They Find?
  • Time & Effort: On average, students spent about 6 months (or 24.5 weeks) using Anki, trying to memorize a whopping 5086 different flashcards!
  • The Score Connection: Here’s the interesting part: students who relied more on Anki and reviewed its flashcards scored higher on the USMLE Step 1 exam. They did better!
  • Firecracker Comparison: On the other hand, students who used Firecracker, the specialized tool just for the USMLE exam, didn’t see any boost in their scores. It seemed like Anki was more helpful than this specialized software.
So, What’s the Big Takeaway? Using Anki and sticking to its flashcards seemed to give medical students an edge. Those who spent time with Anki and its unique way of helping you remember did better when it came to the big medical exam.

2. Anki’s Role in Helping a 72-Year-Old with Language Challenges


Background Story: In 2016, there was a heartwarming study about a 72-year-old woman who faced a challenge called Aphasia. This means she had trouble with language—like remembering and using words.

Her Tool of Choice: To tackle this challenge, she decided to use Anki, a digital flashcard system. Over a period of 20 months, she used Anki to help her remember a list of 139 words.

How Did She Compare?: Now, you might wonder how impressive this is. Typically, people with her specific condition, known as Primary Progressive Aphasia, struggle a lot. Without Anki, they usually only remember about 40 words using other methods. But with Anki by her side, she surpassed that and remembered way more – 139 words, to be exact!

In Simple Terms: Imagine trying to recall 139 items from memory. It’s quite a task! But with the help of Anki, this determined lady managed to remember more words than most people with her condition do with other methods. It’s a testament to how effective Anki can be, even for challenging situations like hers.

3. Anki’s Classroom Success Story with High Schoolers


The Setting: In an American public high school, there’s an English teacher facing a class of mostly 9th and 10th graders. Now, many of these teens aren’t super excited about school or getting top grades. But hey, there are always a few exceptions in every group!

The Game Plan with Anki: Every single day, during their class time, they all jumped into using Anki together. For those not familiar, Anki is a digital tool that helps you memorize things using flashcards.

How They Used Anki:

  • Daily Routine: Each evening, the teacher prepared about 7 new flashcards for the next day’s lesson.
  • Class Session: When in class, they spent roughly 8 minutes going over these cards. That’s a fast pace, tackling about 3.5 cards every minute.
  • Engaging Method: The teacher read out each card for everyone to hear. Then, after giving it a moment, he’d pick a student to answer. Based on their responses and his judgment, he’d tap a button in Anki to keep track of their progress.

The Big Win:

Now, improving reading skills overnight is a tall order. But guess what? The students’ scores on their reading comprehension tests actually improved! They went up from 48% to 52%, which might not sound huge but is a promising step forward.

In Short:

Even with a group of teens not super keen on studying, using Anki in class seemed to make a real difference. Their reading test scores showed a noticeable boost, proving that sometimes a mix of tech and teaching can do wonders!

How Anki Can Benefit Your Company:

Employee Training and Development:

  • Skill Enhancement: Use Anki to create flashcards that reinforce crucial skills, knowledge areas, or company-specific protocols. This ensures employees grasp essential information, leading to improved performance and productivity.
  • Onboarding: For new hires, Anki can serve as a supplementary tool during the onboarding process, helping them quickly acclimate to company culture, policies, and procedures.

Sales and Customer Engagement

  • Product Knowledge: Equip your sales team with Anki flashcards that detail product specifications, benefits, and unique selling points. This ensures they’re well-prepared to address customer inquiries effectively.
  • Customer Retention: Develop flashcards that guide customer service representatives in handling common issues, ensuring consistent and satisfactory resolutions, leading to enhanced customer loyalty.
Strategic Decision Making:
  • Market Research: Create Anki decks that summarize key market trends, competitor analysis, and customer insights. This facilitates informed decision-making and strategic planning.
  • Business Acumen: Develop flashcards that cover essential business concepts, financial metrics, and industry-specific terminology. This ensures leaders and decision-makers possess a robust understanding of critical factors influencing company performance.

Continuous Learning and Innovation:

  • Professional Development: Encourage employees to utilize Anki for ongoing professional development. Whether it’s learning a new software tool, mastering a specific technique, or staying updated on industry trends, Anki can facilitate continuous learning.
  • Innovation Culture: Foster a culture of innovation by utilizing Anki to share groundbreaking research, emerging technologies, and innovative ideas across teams. This encourages collaboration, creativity, and forward-thinking.

Operational Efficiency:

  • Process Optimization: Create Anki decks that outline standard operating procedures, best practices, and workflow optimizations. This ensures consistency, reduces errors, and enhances operational efficiency across departments.
  • Time Management: Develop flashcards that provide time-saving tips, productivity hacks, and effective prioritization techniques. This empowers employees to manage their time more effectively, leading to increased productivity and work-life balance.

How to integrate the Anki algorithm into your system:

Integrating the Anki algorithm into a specific application, platform, or system would typically involve understanding the underlying principles of spaced repetition and the specific functionalities you want to implement.
Here’s a general outline to guide you through the integration process:
1. Understand Anki’s Algorithm:
  • Familiarize yourself with the principles of spaced repetition and how Anki’s algorithm operates. This involves understanding concepts like intervals, ease factors, and review scheduling.
2. Define Objectives and Requirements:
  • Clearly define what you aim to achieve by integrating the Anki algorithm. Whether it’s enhancing user retention, optimizing learning pathways, or improving engagement, having clear objectives will guide the integration process.
3. Select Integration Approach: Determine how you want to incorporate the Anki algorithm. Options may include:
  • Direct Integration: Embedding Anki’s algorithm within your application, leveraging its functionalities for user-specific content delivery and review scheduling.
  • API Integration: Utilizing Anki’s API (if available) to communicate between your application and Anki, facilitating data exchange and synchronization.
  • Custom Implementation: Developing a custom algorithm inspired by Anki’s principles, tailored to your specific requirements and constraints.
4. Develop Integration Strategy: Design a comprehensive integration strategy outlining:
  • Data Mapping: Define how user data, content, and performance metrics will be mapped and synchronized between your application and the Anki algorithm.
  • User Experience: Ensure a seamless user experience by integrating Anki’s functionalities transparently within your application’s interface, maintaining consistency and usability.
  • Scalability: Consider scalability aspects, ensuring the integration can accommodate growing user bases, increased data volumes, and evolving requirements.
5. Implementation and Testing: Implement the integration strategy, developing necessary code modules, APIs, or interfaces to facilitate communication between your application and the Anki algorithm. Conduct thorough testing to validate:
  • Functionality: Ensure Anki’s algorithm operates as expected within your application, maintaining accuracy, reliability, and performance.
  • Compatibility: Verify compatibility across different devices, platforms, and user environments.
  • Security: Implement robust security measures to protect user data, privacy, and integrity throughout the integration process.
6. Monitor, Evaluate, and Optimize:
  • Continuously monitor the integration’s performance, user feedback, and key metrics to evaluate its effectiveness and identify areas for improvement.
  • Optimize the integration based on insights gathered, refining functionalities, enhancing user experience, and adapting to evolving requirements and user needs.


In summary, by leveraging Anki’s capabilities strategically, your organization can achieve its objectives more efficiently, driving growth, innovation, and success in today’s competitive landscape.

Vikas Agarwal is the Founder of GrowExx, a Digital Product Development Company specializing in Product Engineering, Data Engineering, Business Intelligence, Web and Mobile Applications. His expertise lies in Technology Innovation, Product Management, Building & nurturing strong and self-managed high-performing Agile teams.

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