A decision-making aid developed by management theorist Ralph Stacey in the early 1990s. It plots issues on two axes: how much agreement there is among stakeholders, and how much certainty there is about cause and effect. The resulting zones — simple, complicated, complex and chaotic, with a large “zone of complexity” or edge of chaos in the middle — suggest different approaches, from standard procedures in the simple zone to experimentation and adaptation in the complex zone.
It’s often compared with the Cynefin framework. Stacey himself later distanced himself from the matrix, arguing it oversimplified how uncertainty and disagreement actually shift in practice.