In recent years, pianist Ethan Iverson has been collaborating with a number of artists, particularly elder statesmen of the jazz tradition. In 2017, he appeared at the Village Vanguard with trumpeter Tom Harrell. The performances were document on Common Practice, Iverson’s most recent ECM recording. In addition to Harrell, the CD’s personnel includes bassist Ben Street and drummer Eric McPherson, longtime associates of the pianist. The common practice to which the title refers are jazz standards, mostly from the Great American Songbook but also bebop originals. The group investigates a range of styles, from ardent balladry on “The Man I