The Sensible 12: No. 8

8. Communication both internal and external to the project must be clear and frequent.
Almost every aspect of project management is facilitated by the written and spoken word. It is critical that team members communicate often with each other as they work to fulfill the vision of the project. The project manager must communicate progress that the team is making toward their deliverables as well as surfacing issues and risks that arise along the way. It is important that all communication inside and out of the project clearly conveys the appropriate message to the intended audience.

Information is the lifeblood of project success. Much of the discourse on projects is about delivery or schedule; doing things. This is right as far as it goes, but the right things must be done rightly. People need information to do this and need to provide information while they are doing it.

Everyone on the project team must feel free to get any project information they need, and contribute to the project as they see is necessary. That is, no conversations (about the project or its performance) are prohibited. Once freedom of project information and communication is reduced, the  project manager is cut off from knowledge and there's nothing that stands in the way of failure.