One reason she is credited for the whole 3-part harmony concept for choirs is because Thomas A. Dorsey who taught James Cleveland as well as Cleveland followed the classical voice structure of continuing to use baritone/basses in their choirs understanding that it was important that all voices were permitted into choir. Clark recorded the 3-part choir which is how the concept spread and as Pentecostalism became the standard for gospel music trends, that sound became the "black gospel" sound.