If effective communication on a project is vital--and it is--then knowing the objective of any communication must be clearly defined.  Once this specific objective of the communication is known and the person to whom you will be communicating is identified, the potential for success (achievement of the objective) will be significantly increased if you deliver the "message" in a way that makes it easy for the receiver to "get it".  The Strength Deployment Inventory (also known as Motivational Relationship Awareness Theory) helps you decide what style of communication will be most effective in any specific situation.