Hierarchies are versatile frameworks for structuring information.

DEFINITION: Hierarchies are frameworks that rank items by their importance or inclusiveness (detail).

Many aspects of human society are organized hierarchically. Government, business, academia, and of course militaries are all structured using hierarchical frameworks. Hierarchies are important elements of the success of fields such as engineering and computer science (Abelson and Sussman, 1996). Hierarchies are not limited to human endeavors, but organize social systems throughout the animal kingdom. Therefore, hierarchies are an extremely powerful organizational framework.

Not surprisingly, hierarchies can also be extremely useful for structuring reasoning and writing for several reasons:

A) Like most frameworks, hierarchies make writing explanatory by putting information into context. Because hierarchies are ubiquitous, the context of a hierarchy is particularly easy for audiences to understand. For example, hierarchies can help to contextualize otherwise-descriptive frameworks (such as lists).

B) Hierarchies help to limit the amount of information that audiences need to consider at any one time. Using a hierarchical framework allows both authors and audiences to focus attention on a specific subset of information. Hierarchies can contribute to using the power of abstraction to create modular arguments.

C) Hierarchies can help to provide an order for presenting information. Using a hierarchical framework can guide authors when presenting information, and also help audiences to understand the logical flow of an overall argument.

Hierarchical conjunctions can help to identify hierarchical relationships in written arguments.

Many types of hierarchies can contribute to effective communication. Three hierarchies that have practical applications to scientific reasoning and writing are TREE FRAMEWORKS, OUTLINES, and LITERATURE GRIDS.


Hierarchies are powerful ways of organizing information. Tree frameworks can help place information in context and limit the amount of information that must be considered at any one time. Outlines are useful frameworks for organizing communication. Outlines are strongest when the conclusions of reasoned arguments delimit the primary sections of the outline. Literature grids are useful frameworks for organizing literature searches to support hierarchical frameworks.