Using Cynefin's basic 4 categories (but keeping things brief):
- obvious / simple - not typically warranting a project approach; very linear, direct cause and effect; example would be call center, FAQ's.
- complicated - the realm of most waterfall projects; expertise and analytic approaches are useful; cause and effect preserved. My opinion is presumes overall environment relatively static or predictably changing.
- complex - cause and effect obscured, or even absent; better to use an experimental approach (probe, sense, respond, in Snowden's terms); Agile or other iterative approaches more likely to succeed, or just not fail as badly. Pattern identification useful. My belief is overall environment dynamic, and less predictable,
- chaos - turbulent, no sense of predictability or perceived correlation, missing frames of reference for coherence.; well outside domain of project management, other than for very brief periods of exposure. Saving Changes...
While Cynefin or another other categorization framework can help to guide the decision-making process, there are many other variables which need to be considered when choosing the right lifecycle and practices for a given project including its scope, constraints and the EEF's surrounding the project.