Parallel process and isomorphism are two supervisory concepts that are often discussed independently but rarely discussed in connection with each other. These two concepts, philosophically, have different historical roots, as well as different implications for interventions with regard to the supervisory triad. The authors examine the difference between the two concepts, as well as present a new model of decision making, the iso-para/para-iso (IPPI) model, to inform supervisors' interventions in the supervisory triad. (Contains 1 figure.)