The Practice and Benefits of Spaced Repetition – A Method of Scheduling Review Sessions to Maximize Memory Retention

When we learn in classrooms, there is a built in sequence of events that helps us go from initially learning a topic to full mastery. Our mastery of each topic was reinforced multiple times: after learning about the topic, we would do homework involving it, take a quiz the next day, then prepare for said topic to appear in the final exam. After all of these check-ins, we should have effectively retained all the concepts we’ve learned.

What is Spaced Repetition?

Spaced repetition works the same way—in fact, it is defined by Behzad Tabibian et al. (2019) as “a technique for efficient memorization which uses repeated review of content following a schedule determined by a spaced repetition algorithm to improve long-term retention.” In a spaced repetition system (SRS), you are continuously quizzed until you gain mastery of the topic over time.

But where it gets more interesting is having the ability to optimize when you study. Further research has proven that studying something right as you’re on the edge of forgetting it actually helps it stick in your memory more when you do recall that item.

Furthermore, a SRS prioritizes studying things you missed, and studying the things that you know less often, which helps you retain the information effectively while minimizing the amount of time and material you need to review. Minimizing repetitions on material you already have mastered is key to maximizing your allotted study time’s impact on your score.

These reasons, taken together, are why spaced repetition is more efficient than studying the same things constantly.

Advantages of Spaced Repetition

  1. Quizzing while studying is proven to be superior to the study-only approach.

According to Karpicke and Roediger (2003), the “use of repeated testing methodology while learning led to a 45% improvement in test scores over a non-testing study-only approach.” At the foundation of spaced repetition’s effectiveness is the fact that studying with intermittent testing is superior to studying alone. The brain tends to hold onto information better when you use it. If you quiz yourself on what you’ve learned, you’re more likely to master the concept and you are given insight into what topics you’re strong or weak in.

  1. Periodic quizzing is more effective than traditional study methods for memory recall.

As shown by Modigliani and Hedges (1987), “use of distributed practice methodology led to approximately 46% better recall than traditional study methods for the same material.” At the heart of this quote is the word periodic – that is to say, quizzing yourself throughout your studying process is more effective than only quizzing at the end or not at all. Spaced repetition-based studying programs have you reviewing old content consistently while learning the rest for this reason.

  1. Using an algorithmically-optimized study schedule and sorting reduces study time needed to master the material.

When you study with a computerized spaced repetition system, it contains an algorithm that estimates the point that you’ll forget each item you’ve learned. This timing serves two purposes: first, as we said earlier, studying when you’re on the edge of forgetting is more effective and makes the item stick in your memory longer. And second, by establishing the memory strength for each item over time, the SRS system will sort what you need to study in order of what is most urgent. These two principles help an SRS optimize your study schedule to help you remember the most material in the most efficient amount of time possible. In our own experiences, students typically achieve better scores in roughly half the time as traditional methods.

How Achievable Uses Spaced Repetition

At Achievable, we use the spaced repetition method as the backbone of our adaptive learning system, seamlessly creating a personalized study program for students based on their progress through our courses and their strengths and weaknesses. We use our own proprietary spaced repetition algorithm to determine the optimal time for you to review each concept.

The algorithms we’ve created at Achievable can accurately predict when you’re most likely to forget about a concept you’ve learned. When you’re about to forget something, we give you a reminder and schedule a review about that particular concept. This way, we’re able to efficiently keep your retention at their peak levels, while maximizing study time along the way.

The Practice and Benefits of Spaced Repetition - A Method of Scheduling Review Sessions to Maximize Memory Retention

Furthermore, because our SRS is integrated into the course directly, Achievable breaks the course content into discrete learning objectives that are then tied to SRS-powered reviews. There are a lot of distinct objectives – courses have 1,400 – 6,000 reviews each, and each review is tied to a specific learning objective – which gives us a very detailed picture of what you’ve learned. If you get the question right, we move the next review out based on our memory retention model. If you get it wrong, we move the next review up. This is how it helps you save 50% of your study time – you’re refreshing your memory about concepts you don’t know as opposed to wasting time on what you already memorized.

After we estimate your memory strength on each granular learning objective, we then evaluate your mastery of the concept per topic and subtopic as they relate to the exam syllabus. We add extra emphasis to topics that are more common on the exam and make sure you’re using your time most effectively. This is the core of a spaced repetition system.

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