When I was at Design Council an example we referenced was a project which used systems thinking to nudge consumers towards more sustainably-sourced fish.

But when I look for other examples of systems that have changed as a direct result of systems-thinking being used and applied, I can only find lots of good ideas, but little evidence of actual change.

It may well be that I'm looking at the wrong scale, as my understanding is that this approach can also be applied to change systems within an organisation or community.

So what are the best examples you've seen?