Styles and techniques used in a documentary

Observation= Records people in a natural enviroment.
Fly on the wall= Sunjects observed over a period of time.
Interactive= Informs and educates.
Expository=  writing is a type of writing where the purpose is to inform, explain, describe, or define the author's subject to the reader.
Drama documentaries= Dramatic reconstructions.
Mockumentaries= is a type of film or television show in which fictitious events are presented in documentary format.
Personal= Film maker is author and main character.