The object of a requirement determines its category. In addition to functional requirements, some other requirement categories are:

Operational Requirements

Some authors include non-functional requirements in operational requirements.

Development process/program/project requirements

These specify how development and implementation shall be conducted. An example is a requirement that the developer follow a defined, documented process for requirements management. (Unless the organization's product is software, these are not the requirements of core business processes for the management and production of the organization's product or service.)

Contract requirements

The contract may also include functional, non-functional, process, and operation requirements as part of the statement of work.

Performance requirements

Various authors categorize these requirements differently. For example, "flexibility" might be categorized as a quality requirement instead of a performance requirement.

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Nonfunctional requirements: trigger questions for thinking about them

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Page updated 6/2/2012
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