What is "controllerism"

Controllerism is the art and practice of using musical software controllers, e.g. MIDI, Open Sound Control (OSC), joystick, etc., to build upon, mix, scratch, remix, effect, modify, or otherwise create music, usually by a Digital DJ or Live PA performer, often called a "controllerist". Controllerism is also a nod to traditional musicianship and instrumental-ism paired with modern computer sequencing software such as Ableton Live and Native Instruments Traktor. However a working knowledge of scales and chords is not necessarily required as the performers typically focus their efforts more on sequencing events, software effect and instrument manipulations using buttons, knobs, faders, keys, foot switches and pedals than on instrumental notes played in real time.