Statistics window

The statistics windows, Statistics and Element data can most conveniently be viewed by pressing F5 (or choosing Window : Classic). This arranges the statistics windows in the classic shape first introduced in SuperMemo 3.0 (1988).

Learning parameters displayed in the statistics window:

  • Date - current date
  • First day - date on which the learning process began in the given collection
  • Day - number of days in the learning process (i.e. number of days between Date and First day)
  • Memorized - total number of items introduced into the learning process with options such as Learn or Remember. If an item takes part in repetitions it is a memorized item
  • Pending - total number of elements (i.e. topics or items) that have not been yet introduced into the learning process but still away memorization with Learn, Learn : New material, Remember, etc. All pending items are kept in the so-called pending queue that determines the sequence of learning new items. Dismissed items are not present in the pending queue.
  • Dismissed - total number of elements (i.e. topics or items) that have been excluded from the learning process and are kept only as reference material. Dismissed items are neither pending nor memorized. All topics that are stored in the pending queue are dismissed automatically after the first presentation (see: Topics vs items)
  • Total - Total number of topics and items in the collection. It is worth noting that Memorized+Pending+Dismissed=Total. Deleted elements do not contribute to the total count of elements in the system.
  • Outstanding 0+0 - number of outstanding items schedule for repetition on a given day. The first number (before the plus sign) indicates the number of items scheduled for this given day and not yet processed. The second number (after the plus sign) indicates number of items that have already been repeated today but scored less than Good (4). Those are the items that make up the final drill queue.
  • Default FI - default forgetting index given to all new elements added to the system. Forgetting index, in genera, is the proportion of items that are not remembered during repetitions. The lower the value of the forgetting index the better the element is remembered but the more repetitions will be afforded to it. Optimum value of the forgetting index falls into the range from 7% to 13%. Too low forgetting index makes learning too tiresome due to a prohibitively large number of repetitions. All elements can have their desired forgetting index set individually. By default all elements receive initially the forgetting index equal to Default FI. The easiest way to change the forgetting index of a large number of elements is to use Forgetting index option on the pop-up menu in the contents window
  • Average FI - average forgetting index which says what is the average value of the forgetting index in the entire collection. If forgetting index of individual elements is not changed manually, Average FI is equal to Default FI.
  • Measured FI - the value of forgetting index as measured at repetitions, i.e. the actual proportion of items not remembered at the moment of repetitions. It is quite normal to have Measured FI higher than Average FI. This is due to two factors: (1) no learning process is perfect and every user will experience delays in repetitions from time to time, (2) SuperMemo imposes some constraints on the length of intervals that make it sometimes schedule repetitions later than it would be implied by the forgetting index. The constraints in computing intervals, for example, prevent the new interval to be shorted than the old interval (except for the situation in which the item has been forgotten). For low values of forgetting index and items with low A-Factor, the new interval might often be shorted than the old one!
  • Burden - average number of repetitions per day. This value is equal the sum of interval reciprocals (i.e. 1/interval). The interpretation of this approach is as follows: every item with interval of 100 days is on average repeated 1/100 times per day. Thus the sum of interval reciprocals is a good indicator of the total repetition workload in the collection.
  • Repetitions - average number of repetitions per memorized item in the collection.
  • Lapses - average number of times individual elements have been forgotten in the collection (only memorized elements are averaged).
  • Interval - average interval of memorized items in the collection.
  • A-Factor - average value of A-Factor among memorized items in the collection. A-Factor is a measure of item difficulty. The higher the A-Factor, the easier the item
  • Last Rep - average date of the last repetition among memorized items in the collection
  • Next Rep - average date of the next repetition among memorized items in the collection
  • Test - number of items in the random test queue (used only at running random tests from Tools : Random tests)

1.3.50