a slew of reasons, most fail.
In my consulting career, I've come across six types of project managers who do it the wrong way.
Certain PMs fear conflict and agree to every demand that internal clients or senior management make. These PMs might have a sales background. As a result, they are used to saying "yes."
Now, these PMs typically mean well and certainly do not intentionally try to sabotage projects. Often, yes-men simply want their clients to be satisfied and provide future references. But by failing to confront those with wildly different expectations, yes-men implicitly make promises and commitments that endanger entire projects.
Much like yes-men, micromanagers often mean well and merely want to understand each step in a process or the nature of a complex issue. However, on a project, the PM is not supposed to be the product, application or technical expert. During crunch time, consultants often cannot explain each facet of a complex issue to anyone, much less a newbie, regardless of the latter's benevolent intentions.
[ Bone up on the pros and cons of a project management office. Read Project Management Offices: A Waste Of Money? ]
Micromanagers need to let experienced consultants do their jobs. Depending on the timing, a PM might have to live with a high-level explanation of an issue. Should the micromanager need more detail, she should bring consultants to steering committee meetings or have them write status reports providing more specifics.
PMs need to let everyone else breathe; that is, get the actual work done. Employees and consultants can't be effective if they spend most of their time briefing PMs on the status of each issue. This is especially true as projects reach critical points.
PMs who routinely fail to deliver are the worst of the bunch. At a minimum, they cause organizations to miss project deadlines. Procrastinators put both employees and consultants in untenable positions. Speaking from a consultant's perspective, it's a no-win situation. The procrastinator often ducks clients and does not deliver promised results such as updated project plans, documentation or status updates. In such cases, people are likely to lose faith in the consulting firm and its individual consultants, whether the latter are contributing to the delays or not. The best PMs know when to use each tool in their kits.