http://www.pinnacle-strategies.com/Critical%20Chain.htm
Since critical path was invented in 1950’s, it has created a multi-billion dollar industry worldwide. The Gartner Group estimates that companies spend close to $2 billion per year on early generations of project management software and associates services. Even with so much investment, it is regrettable that most projects, regardless of industry or type, are delivered late, over budget and under scope.