There is an interesting US Government report out in draft on reporting scientific uncertainty. Buried inside is this nugget (my italics):

The importance of continued and iterative empirical evaluation of the effectiveness of communication is stressed.

One key finding in this literature is that there is no such thing as an expert in communication – in the sense of someone who can tell you ahead of time how a message should be framed, or what it should say. Empirical study is absolutely essential to the development of effective communication.