Skill 4: Repetition and review

SuperMemo is based on repetition. You will review the learned material from time to time to make sure you prevent forgetting.

If you have never tried SuperMemo before, you will need to get the hang of standard repetitions as described here.

In incremental reading, your review will be based on similar principles as in classical SuperMemo. The main differences are:

• the learning process will intermingle reading of new articles with reviewing your items
• your items will mostly have a form of cloze deletions, i.e. sentences with a question posed by a missing part [...] (e.g. The planet nearest the Sun is [...] )
• as the entire learning process is incremental, your cloze deletions will often show up in an unfinished form

Incrementally processed articles will be subject to periodic review/reading. When you resume reading an article after a certain period, you will proceed to new sections, extracting newly acquired wisdom into separate elements with Alt+X (i.e. Remember extract). Usually, you will delete the remnants of the processed article with Delete before cursor (Alt+\).

The algorithms that determine the timing of (1) repetitions of question-and-answer material and (2) reviewing reading material are analogous but not identical. Most importantly, all repetitions and article presentations happen in increasing intervals by default. In incremental reading, you will see a constant inflow of new articles into your collection. Unprocessed material will need to compete with the newly imported material. Increasing review intervals make sure that your old material fades into lower priority if not processed early. The speed of processing will depend on the availability of your time and the value of the material itself. Articles that are boring, badly written, less important for your work or growth, will receive smaller portions of your attention and may go into long review intervals before you even manage to pass a fraction of the text. That is an inevitable side effect of a voluminous flow of new information into your collection and into your memory. However, intervals and priorities can easily be adjusted. If your priorities change, you can modify the way you process important articles. At review time, you can either read the entire article without interruption, or bring it back for review in a shorter interval. You can manually change its priority (e.g. with Alt+P). You can also use search tools (e.g. Ctrl+F) to locate more articles on the subject that you feel you have neglected. You can reprioritize a bunch of articles by changing their priority. You can shorten intervals of articles, or review them all when needed (see: Subset review).

The algorithm for reviewing questions and answers (e.g. cloze deletions) is quite complex and limits your influence on the timing of repetitions (see: SuperMemo Algorithm). This is to ensure that you achieve a high level of knowledge retention, which might be compromised by manual intervention. However, the algorithm for determining inter-review intervals for topics is much simpler and is entirely under your control. Each article receives a specific priority. The priority determines which articles are reviewed first and which can be postponed in case you run out of time. Each article is also assigned a number called the A-Factor that determines how much intervals increase between subsequent reviews. For example, if A-Factor is 2, review intervals will double with each review. Priority and A-Factors are set automatically, but you can change them manually at any time. Priorities and A-Factors are determined and modified heuristically on the basis of the length of the text, the way it is processed, the way it is postponed or advanced, and by many other factors. You can change the priority and A-Factor of an article by pressing Alt+P. You can also use Shift+Ctrl+Up arrow and Shift+Ctrl+Down arrow to increase or decrease an element's priority. Note that A-Factors associated with items cannot be changed by the user, as they are a reflection of item difficulty that determines the length of optimum inter-repetition intervals (see: Forgetting index).

You can control the timing of article review by manually adjusting inter-review intervals. Use Ctrl+J (Reschedule) or Shift+Ctrl+R (Execute repetition) to determine the date of the next review. Ctrl+J will increment the current interval, while Shift+Ctrl+R will first execute a repetition and then set the new interval. For example, if your current interval is 100 and you specify the value of 3 in Reschedule, your new repetition date will be set in 3 days, and the last repetition date will not change (the new interval will be 103). If you do the same with Execute repetition, your new interval will be 3 and the last repetition date will be set to today. In other words, Reschedule increments the interval (it can also shorten intervals), while Execute repetition sets the length of the interval (while leaving a trace of a repetition executed in the learning process). Note that Reschedule (Ctrl+J) executed at Next repetition stage will first complete the repetition and will have the same effect as Execute repetition (Shift+Ctrl+R). To delay a repetition during learning, use any of the earlier stages of the repetition cycle.

In a heavily overloaded incremental reading process, you will often want to focus on a specific subject on a given day (e.g. before an exam). For that purpose, read about the priceless tool: subset learning.

Summary

• use the Learn button to process, learn, and review all your knowledge
• the review of items is handled by the SuperMemo Algorithm. Grade your items well, formulate them well, and mark them with honest priorities. SuperMemo will take care of the rest
• review of topics/articles also occurs in increasing intervals, however, you can always manually set the next date with Execute repetition (Shift+Ctrl+R). Make sure you mark your top articles with high priority. Otherwise, they can quickly fade from view