Quantity and quality of musical practice as predictors of performance quality.

Twenty-two pianists, classified into four levels of skill, were asked to learn and memorize an assigned composition by J. S. Bach (different for each level). All practice was recorded on cassette tape. At the end of the learning process, the pianists performed their composition in a recital setting. The resulting performances were evaluated by three experienced piano teachers. From the cassette tapes, values for the quantity of practice were obtained. These values were compared across all four levels of skill and examined to reveal whether they were related to quality of performance. The analyses indicate that the standard deviations of the amount of time spent in each practice session increased systematically with level of skill and that pianists at higher levels spent more time in each practice session. Quantity of practice, however, was not significantly related to quality of performance. Rather, pianists who employed longer practice segments by the middle stage of practice produced better musical, communicative and technical performances. These findings stand in defiance of the argument that quantity of practice is the fundamental determinant of the quality of performance. Instead, they suggest that the content and quality of an individual's practice must be examined when investigating the determinants of musical skill.