Theory Question from a Neophyte

[Mark Revels]

Hello Linguists!

I am a doctoral student studying the use of computer mediated
communication in higher education. I am looking for an extant theory
that rates the use of verbal communication in comparison to other
forms. For example, has verbal communication been shown to be the most
effective, efficient, etc.?

Also, I would be interested in knowing about linguistic/communication
theories that compare verbal communications to other forms,
specifically in the context of learning.

Any help in this area would be much appreciated!

Mark