The meta-model was originally presented in The Structure of Magic I: A Book About Language and Therapy in 1975 by Richard Bandler and John Grinder, the co-founders of neuro-linguistic programming.
The function, then, of the Meta Model is to help us identify problematic deletions, distortions and generalizations in our internal thinking patterns and our communication skills.
As described by Bandler and Grinder, "Deletion is a process by which we selectively pay attention to certain dimensions of our experience and exclude others. For example, the ability that people have to filter out or exclude all other sound in a room full of people talking in order to listen to one particular person's voice... Deletion reduces the world to proportions which we feel capable of handling. The reduction may be useful in some contexts and yet be the source of pain in others."
"Distortion is the process which allows us to make shifts in our experience of sensory data. Fantasy, for example, allows us to prepare for experiences which we may have before they occur... It is the process which has made possible all the artistic creations which we as humans have produced... Similarly, all the great novels, all the revolutionary discoveries of the sciences involve the ability to distort and misrepresent present reality."
"Generalization is the process by which elements or pieces of a person's model become detached from their original experience and come to represent the entire category of which the experience is an example. Our ability to generalize is essential to coping with the world... The same process of generalization may lead a human being to establish a rule such as, 'Don't express any feelings.'"
The meta-model include Simple Deletions, Unspecified Nouns, Unspecified Adjectives, Unspecified Verbs, Unspecified Referential Index, Nominalizations, Modal Operators, Presuppositions, Universal Quantifiers, Cause - Effect, Mind Reading, Complex Equivalence, Lost Performative...etc.
The Meta Model helps a client to be more specific about his problem and as a result he can find out the possible solutions.