Element data 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).

Element data displayed on the left of the element data window:

**Repetitions -**number of repetitions afforded the item whose data is being displayed. If the item had been forgotten, the number of memory lapses is displayed in parentheses**Interval**- current interval of the item, i.e. the number of days between**Last repetition**and**Next repetition**.**Last repetition**- date of the last repetition of the item**Next repetition**- date on which the next repetition of the item should take place**A-Factor**- A-Factor associated with the item. A-Factor is the measure of item difficulty. The higher the A-Factor, the easier the item. The most difficult items have A-Factor equal to 1.3**U-Factor**- quotient of the old interval and the new interval. Only in items that have been repeated only once, U-Factor equals the first interval. U-Factors makes up an important element of the Algorithm SM-8. If you do not know the algorithm, U-Factor does not have much meaning to you**Forgetting index**- planned probability of forgetting the item in the next repetition (in percent). Forgetting index can be changed to a desired value (e.g. with**Forgetting index**on the pop-up menu in the contents window). For example, if the forgetting index is 10%, you stand a 90% chance that you will remember the item in the next repetition**Future repetitions**- estimated number of repetitions of the item in the next thirty years. This value is easily derived from**A-Factor**,**Repetitions**and the matrix of optimal factors (see Algorithm SM-8)**First grade**- grade obtained by the item in its first repetition. This value is important as the first grade vs. A-Factor correlation is used to quickly determined A-Factor of items right after their first repetition**Ordinal**- ordinal number associated with the element. Ordinals can be used to sort items in the pending queue, final drill queue, etc. The lower the ordinal, the higher the priority of the item. Ordinals range from 0 to 100**Type -**type of the element: item or topic (see also: Topics vs. items)**Status**- current status of the element: dismissed, pending or memorized

To understand repetition parameters displayed on the right of the element data window you should have a rudimentary knowledge of Algorithm SM-8:

**Repetitions-**number of repetitions afforded the item whose data is being displayed (after the current repetition). If the item had been forgotten, the number of memory lapses is displayed after the colon. The number in the parentheses indicates the number of repetitions that the item would need to reach its current interval assuming the current value of the matrix of optimal factors and no memory lapses on the way. This hypothetical value is indeed used to index the matrix of optimal factors and the matrix of retention factors in computing the new values of individual entries at repetitions**Optimum interval**- optimum interval the item should use to ensure the forgetting probability determined by**Forgetting index****New interval**- new interval given the item.**New interval**might optimally be equal to**Optimal interval**; however, two factors may make these two values differ: (1) minor interval dispersion is needed to avoid scheduling a large number on the same day (interval dispersion also speeds up the convergence of the optimization algorithm), and (2) some constraints imposed on the new interval may make it impossible for it to equal**Optimum interval**. For example, the new interval cannot be shorter than the old interval (**Interval**). For low forgetting index, it is quite common for**Optimal interval**to be shorter than**Interval**. This is not a reason to worry about the learning process; however, might be an indication that the forgetting index is set too low**Next repetition**- date on which the next repetition should take place (after the current repetition)**New A-Factor**- new value of A-Factor estimated for the item after the repetition**New U-Factor**- new value of U-Factor (i.e. the quotient of the new interval and the old interval; see**U-Factor**above for more)**Expected FI**- forgetting index derived from the interval (see the description of the Algorithm SM-8)**Estimated FI**- forgetting index derived from the grade (see the description of the Algorithm SM-8)**Normalized grade**- grade normalized for forgetting index equal 10% (see the description of the Algorithm SM-8)**R-Factor change**- change of the R-Factor corresponding to the current repetition number (the one displayed in parentheses at**Repetition**) and A-Factor (displayed at**A-Factor**among element parameters described earlier)(see the description of the Algorithm SM-8)**O-Factor change**- change of the O-Factor corresponding to the current repetition number (the one displayed in parentheses at**Repetition**) and A-Factor (displayed at**A-Factor**among Item parameters described earlier)(see the description of the Algorithm SM-8)**Cases**- number of repetition cases used to compute the values of O-Factor and R-Factor corresponding to the current repetition number (the one displayed in parentheses at**Repetition**) and A-Factor (at**A-Factor**in previous column)(see the description of the Algorithm SM-8)

When you double-click the element data window, you can view the element's repetition history