According to the Flight Safety Foundation (FSF) Approach-and-landing Accident Reduction (ALAR) Briefing Note 2.1 — Human Factors, "Effective communication is achieved when our intellectual process for interpreting the information contained in a message accommodates the message being received."
The briefing note summarises the process as follows:
How do we perceive the message?
How do we reconstruct the information contained in the message?
How do we link the information to an objective or to an expectation?
What amount of bias or error is introduced in the process?
and points out that the "following factors may affect adversely the understanding of communications: