Lately I have been speaking to as many audiences as I can about the need to focus on complex behavior rather than on complex systems. The reason is that there is no practical way to apply the notion of a “complex system” to practical decisions about program models, metrics, or methodology. But it is possible to make those decisions with respect to the things that complex systems do. I just completed a series of three short “coffee break” sessions on this topic for the American Evaluation Association.
Go here for the slides.
www.jamorell.com/documents/AEA_Coffee_Break_Part_1.pdf
www.jamorell.com/documents/AEA_Coffee_Break_Part_2.pdf
www.jamorell.com/documents/AEA_Coffee_Break_Part_3.pdf
If you are a member of AEA you can also hear the audio presentation. Go here for the audio tapes.
https://vimeo.com/269709240/e1b05b4857
Evaluation Uncertainty 
I think you are making an important distinction Jonny. I’d only have a couple of concerns. One is that you may be inadvertently giving permission for evaluators to continue to talk ill informed crap about complexity, because in effect you are say that they don’t have to worry about the theory any longer. Secondly in the slides you switch between complex behaviours and complex adaptive behaviours. Which do you mean?