Ralph Douglas Stacey, professor of management theory at Hertfordshire Business School, UK, invented the so-called Stacey-Matrix. In its original form, the Stacey-Matrix deals with decision-making in complex organizations. Today, the Stacey-Matrix is often combined with the Cynefin framework.
The matrix depicts on the vertical axis WHAT a project should achieve (the requirements). On the horizontal axis, the matrix shows HOW the goal could be achieved — by which technology, methods, frameworks, etc. In more detail, the WHAT axis spans from clear requirements to unclear, ambiguous ones. The horizontal HOW axis spans from known to unknown technologies.
If the WHAT is clear and also the way to get there (the HOW), then the project is classified as "simple". Few surprises are to be expected in the project, experience and routines can be drawn upon, and the process is known or easily predictable. In a simple environment, we should "look, classify, deduce, react" (or "simply do it").
The Stacey-Matrix classifies a project or enterprise as "complicated" the more unclear the HOW and/or the WHAT becomes. The number of variables increases to the point that they are no longer easily manageable. However, the project is still easily predictable because the variables follow a linear causality. In a complicated environment, we should react best in an inspect-analyze-respond mode.
With increasing uncertainty of the HOW and WHAT the enterprise shifts from complicated to "complex". In this case, there are very many risks, requirements are not known at all or not down to the last detail, and they interact with each other. It is also not certain with which methods and techniques the project goal can best be achieved. We cannot be predicted what exactly will happen. In a complex environment, we should react best in an agile, iterative mode in a probe-inspect-react way.
The Stacey-Matrix calls situations where as well the goals, requirements and possible solutions are unclear, "chaotic". Chaotic environments have a high risk of failure since they show no recognizable patterns.
- Wikipedia: Ralph D. Stacey, https://en.wikipedia.org/wiki/Ralph_D._Stacey.