Complex is not the same as Complicated...
...well, it isn't according to the Harvard Business Review article - A Leader's Framework for Decision Making - by David Snowden and Mary Boone that, deservedly, has just won an award from Emerald (a publisher of research work). The article explains a set of organisational situations - termed Simple, Complicated, Complex and Chaotic - and how to manage them. It is excellent and well worth the $6.95 HBR will want from you for the pleasure of reading it.
There is a lot of good stuff in the article but, for me, its exposition of the difference between Complicated situations and Complex ones is the important bit. I think that plenty of stuff goes wrong (not least in Government IT) because folks try to deal with Complex situations using Complicated strategies. I won't explain: you'll need to read the article.
The article is based on David Snowden's Cynefin Framework, the theory of which you can see him explain in this YouTube video. My earlier post about Wicked Problems also talks about the same ideas. But read the article.