The testing effect […] suggests long-term memory is increased when some of the learning period is devoted to retrieving information from memory. It is different from more general practice effect, defined in the APA Dictionary of Psychology as “any change or improvement that results from practice or repetition of task items or activities."[
Retrieving a piece of information from memory will increase ones ability to recall that piece of information over long periods of time. A common example would be using tests as a tool for study. The student has to attempt to recall the information from memory while taking the test and thereby improves their recall.