Jazz can be hard to define because it spans fromRagtimewaltzes to 2000s-era fusion. While many attempts have been made to define jazz from points of view outside jazz, such as using European music history or African music, jazz criticJoachim Berendt argues that all such attempts are unsatisfactory.One way to get around the definitional problems is to define the term “jazz” more broadly. Berendt defines jazz as a "form of art music which originated in the United States through the confrontation of blacks with European music"; he argues that jazz differs from European music in that jazz has a "special relationship to time, defined as 'swing'", "a spontaneity and vitality of musical production in which improvisation plays a role"; and "sonority and manner of phrasing which mirror the individuality of the performing jazz musician".
Travis Jackson has also proposed a broader definition of jazz which is able to encompass all of the radically different eras: he states that it is music that includes qualities such as "swinging', improvising, group interaction, developing an 'individual voice', and being 'open' to different musical possibilities". Krin Gabbard claims that “jazz is a construct” or category that, while artificial, still is useful to designate “a number of musics with enough in common to be understood as part of a coherent tradition”.
While jazz may be difficult to define, improvisationis clearly one of its key elements. Early blues was commonly structured around a repetitive call-and-response pattern, a common element in the African American oral tradition. A form of folk music which rose in part from work songs and field hollers of rural Blacks, early blues was also highly improvisational. These features are fundamental to the nature of jazz.
While in European classical music elements of interpretation, ornamentation and accompaniment are sometimes left to the performer's discretion, the performer's primary goal is to play a composition as it was written.In jazz, however, the skilled performer will interpret a tune in very individual ways, never playing the same composition exactly the same way twice. Depending upon the performer's mood and personal experience, interactions with fellow musicians, or even members of the audience, a jazz musician/performer may alter melodies, harmonies or time signature at will. European classical music has been said to be a composer's medium. Jazz, however, is often characterized as the product of democratic creativity, interaction and collaboration, placing equal value on the contributions of composer and performer, 'adroitly weigh[ing] the respective claims of the composer and the improviser'.
In New Orleans and Dixieland jazz, performers took turns playing the melody, while others improvised countermelodies. By the swing era, big bands were coming to rely more on arranged music:arrangements were either written or learned by ear and memorized – many early jazz performers could not read music. Individual soloists would improvise within these arrangements. Later, inbebop the focus shifted back towards small groups and minimal arrangements; the melody (known as the "head") would be stated briefly at the start and end of a piece but the core of the performance would be the series of improvisations in the middle. Later styles of jazz such as modal jazz abandoned the strict notion of achord progression, allowing the individual musicians to improvise even more freely within the context of a given scale or mode. The avant-gardeand free jazz idioms permit, even call for, abandoning chords, scales, and rhythmic meters.