Most cultures use at least part of the concept of preconceiving musical material, or composition, as held in western classical music. Even when music is notated precisely, there are still many decisions that a performer has to make. The process of a performer deciding how to perform music that has been previously composed and notated is termed interpretation.
In some musical genres, such as jazz and blues, even more freedom is given to the performer to engage in improvisation on a basic melodic, harmonic, or rhythmic framework. The greatest latitude is given to the performer in a style of performing called free improvisation, which is material that is spontaneously "thought of" (imagined) while being performed, not preconceived. According to the analysis of Georgiana Costescu, improvised music usually follows stylistic or genre conventions and even "fully composed" includes some freely chosen material (see precompositional). Composition does not always mean the use of notation, or the known sole authorship of one individual.
Music can also be determined by describing a "process" which may create musical sounds, examples of this range from wind chimes, through computer programs which select sounds. Music which contains elements selected by chance is called Aleatoric music, and is often associated with John Cage and Witol Lutosławski.
