Why do all experts disagree with each other? It's because all of them express their opinions using a very limited frame of reference. Even the busiest consultants and project managers on earth can only experience an extremely small number of software projects in real life. It's like they are all making statements about biological systems in general after having only had first-hand experience with dung beetles in South Africa.
Am I any different? Well, yes! First of all, I try not to draw any conclusions from my own experience. I try to find and evaluate all other people'sexperiences before forming any opinion of my own. (My own experiences usually turn out to be special and limited forms of very generic patterns.) Second, I try to match any findings with theoretical and practical findings in systems theory. Third, I have only limited experience with dung beetles in South Africa.