Tampering dynamics: SD-SPC insight

Abstract

Integrating statistical process control (SPC) with the system dynamics (SD) modeling method gives process managers superior insight into the processes they must manage. This is what replicating Deming's funnel experiment through a SD model shows. SD allows looking at the experiment causally, as opposed to merely looking at coincidental, due to randomness, SPC charts. Looking under the hood, so to speak, one can see how circular, feedback-loop relations among variables in the funnel experiment produce tampering dynamics, as the distribution of control among deterministic feedback loops determines system behavior. Enhancing SPC with system dynamics can help detect, explain and prevent tampering with the processes that managers must manage.