Nystrand, Cohen, & Dowling (1993)

Genre Categories: Classification of the Informational Uses of School Writing2

Report

Retrospective account of particular events or series of events. (This is what happened.)
Summary
Generalized narrative or description of a recurrent pattern of events or steps in a procedure. (This is what happens; this is the way it is done.)
Analysis Generalization and classification related to a situation, problem, or theme, with logical or hierarchical relationships among generalizations implicit or explicit.
Theory Building and defending at a theoretical level, including implicit or explicit recognition that there are alternative perspectives. Hypotheses and deductions from them.
Persuasion Convincing overrides other functions.