The Forgetting Curve and Spaced Repetition
In 1885, Herman Ebbinghaus coined the term "Forgetting curve". He used this idea to illustrate that when we make no attempts to retain information, we lose that information at an exponential rate.
The forgetting curve is the reason why we all need to review and practice what we learn. If you have a test in a week, and you forget to review that day's lesson, chances are you will only remember 10%-20% of what was covered in class.
Flattening the Curve with Spaced Repetition
Luckily, there is a simple solution to smoothing the forgetting curve and integrating what you've learned into your long term memory: Spaced Repetition. Basically, by reviewing and testing yourself on the material over an extended period of time, you constantly reset the forgetting curve. In doing so, the rate at which you forget information decreases, until you eventually store your coursework in your long term memory.
How to use Spaced Repetition
Preset Intervals - the easy way
The simplest way to incorporate spaced repetition into your study schedule is to have preset intervals during which you review certain material. For example, lets say I set my intervals to be a day, two days, a week, and a month after I first learn something. In my calendar, I would make a note at those dates in the future after finishing a lesson. This method is convenient because it saves you from actively having to evaluate and decide what to review on a certain date. However, due to it's rigidity, you may find yourself not reviewing difficult subjects enough.
Retrospective Revision Time Table - the ideal way
The method of using a retrospective calendar was developed by Ali Abdaal, a Cambridge Graduate and current junior doctor in the UK. Basically, it requires you to evaluate your performance after reviewing (hopefully you're still using active recall), and then based on your past review sessions decide what to look at next. While this does take a bit more time and effort than using preset intervals, it has the benefit of allowing you to focus on what needs your attention.
In essence, every time you review a subject, make a note of the date and how well you performed on your active recall questions. In the future, you should be able to look back and decide what to review based on how well you did and how much time has passed.
Bonus: Anki Flashcards
The flashcard app Anki automatically incorporates spaced repetition into your review sessions based on your performance and how long its been since you revised a particular topic. Anki should be used in conjunction with either of the two above methods.
