Theory
Information richness is defined by Daft and Lengel as "the ability of information to change understanding within a time interval".[2]
Media richness theory states that all communication media vary in their ability to enable users to communicate and change understanding - their "richness".[5] Communications that can overcome different frames of reference and clarify ambiguous issues to promote understanding in a timely manner are considered more rich. Communications that take a longer time to convey understanding are less rich. One main purpose of choosing a communication medium is to reduce the equivocality of a message. Equivocality exists when there are multiple and possibly conflicting interpretations for the information or the framework with which to interpret it.[5] If a message is equivocal, it is unclear and thus more difficult for the receiver to decode. The more equivocal a message, the more cues and data needed to understand it, and media richness theory places communication mediums on a continuous scale that represents the richness of a medium and its ability to adequately communicate a complex message.[6] For example, a simple message intended to arrange a meeting time and place could be communicated in a short email, but a more detailed message about a person's work performance and expectations would be better communicated through face-to-face interaction.
The theory includes a framework with axes going from low to high equivocality, and low to high uncertainty, with low equivocality and low uncertainty being a clear, well-defined situation, and high equivocality and high uncertainty being ambiguous events that need clarification by managers. Daft and Lengel also stress that message clarity may be compromised when multiple departments are communicating with each other, as departments may be trained in different skill sets or have conflicting communication norms.