Here is an interesting point that Lauri Koskela and Greg Howell mention in their article I forgot to mention in my previous posting about the fundamental problems concerning plan-driven methods. The lack of information about how the project plan should actually be performed. For example, the PMBok guide is amazingly brief about this.

So, management creates a plan, throws it to the working people, and that is about it; no comments on how the working people should operate. We all know that to start a specific task, some of the needed materials or resources might be missing. Then the informal and creative process of fixing and improvisation will start to allow to start on the task anyway, or to minimize the effects on other activities.

Although the execution of project tasks consist for a large part of improvising to make the scheduled tasks happen, the plan driven methods provide no underlying basics for the execution. There is just the plan, and if something has to be changed, it start by changing the plan. And thats all there is to it.