A perfectly skilled and competent agile team may still fail. It's the same problem as when healthy animals are released into a habitat that is being decimated. They don't have a real chance to survive even though each individual knows how to survive. The highest priority projects should go to agile teams. Portfolio managers will have to regularly kill off those projects that cannot deliver or that are vying with Agile projects for resources.
If teams have mastered bug-free code, are empowered, and their work stream is properly controlled, they can still be destroyed by the failure of managers to match the organization's work flow to its sustainable capacity. One more time: Managers at every level have got to buy into the idea that they must never jam more work into a pipeline than its proven capacity.
Lean Thinking and Agile belong together for creating software-intensive products and services. They are actually different names for parts of one unified concept.
The Comet team got into quite a difficult situation even though they were in good shape when the external coaching ended. Once problems accumulate to this degree, it is very difficult to sort them out - too much so for an organization still getting used to agile. The key is to prevent these problems by understanding the control points in an agile system.
Too often it is easy to dismiss those control points when they involve so-called "soft" skills like good facilitation, or when people feel too much time pressure to clean up a "quick fix". Agile adoption must be led by executives and managers who thoroughly understand its dynamics. Otherwise, the normal frictions that arise will completely erode the agile adoption programme.
Agile is not just new software development techniques, or new project management techniques. It is that and more - it is an overall management philosophy for an organization. Agile points the way to applying Lean Thinking to software-intensive parts of product development, and of business process improvement. Comet's managers had adopted lean-agile practices but had not yet fully grasped its management philosophy.
The biggest gains of all come from management innovations. Management innovation is very hard to copy because it is almost invisible from the outside. Practices are easy to see and copy but copying them seldom produces sustainable benefits within an incompatible system of management. Lean businesses are radically different from traditional businesses in almost every respect. This is why it is so difficult to move an organization fully to lean-agile methods. It's also why big rewards still await those who get there first.
 The term "Agile" is used to mean any approach that addresses lean software development together with lean management. Scrum plus Extreme Programming does that. So do DSDM and Crystal, to mention a few.
 The term "stakeholders" is intended to include customers, or those who represent them, representatives of other groups within the company that are affected by the agile project, and groups whose cooperation is needed by the agile team.
 "Embedded Agile Project by the Numbers With Newbies", paper presented at Agile 2006 conference by N. Van Schooenderwoert. Available at http://www.leanagilepartners.com/publications.html. The author found many other agile teams who had similar successes but had not produced detailed metrics. They typically said that they don't track bugs because they're so rare - maybe one in a month. They sometimes could not recall when they last had a bug.
 There are many factors involved beyond just the number of tests. The quality of tests matters, as well as how easy or difficult it is