Knowledge acquisition rate
Knowledge acquisition rate (aka speed of learning) is the speed of memorizing new items. Acquisition rate is usually expressed in items memorized per year per minute. For example, if 20 minutes a day result in memorizing 10,000 items per year, the acquisition rate is 500 items/year/min (10,000/20=500). In SuperMemo, the acquisition rate may vary from 30-1000 items/year/minute depending on the difficulty of the material, the forgetting index, and the stage of the process. Most users report 100-400 items/year/minute. Acquisition rate may decrease substantially in the first year only to stabilize asymptotically as years pass by.
The formula for knowledge acquisition rate is:
AcquisitionRate = Memorized/(Days/365.25)/TimePerDay
where:
- AcquisitionRate: speed of learning
- Memorized: total number of memorized items
- Days: total number of days of learning
- TimePerDay: time invested in learning every day
See also:
This glossary entry is used to explain SuperMemo, a pioneer of spaced repetition software since 1987
.png)
Figure: Projected course of lifelong knowledge acquisition in spaced repetition. The curve was compiled with the use of data from users of different ages. The middle course of the projected curve has been replaced with actual data from my own 32-years-long learning process (Piotr Wozniak, December 28, 2019). Instead of using the usual metric, i.e. the count of items, the curve uses the sum of retrievability estimates for the collection. All perceived accelerations in learning, e.g. caused by innovations in incremental reading, turned out largely illusory. This raises an exciting possibility that the overall speed of learning may be relatively constant as suggested by some properties of memory derived from the neurostatistical model of memory. The projected slowdown at older ages is hypothetical and may be associated with inevitable aging rather than with the limit on the size of the concept network