Requirements Development Overview

Requirements development is a process that consists of a set of activities that produce requirements for a product. The systems engineering standard [EIA 632] defines “requirement” as “something that governs what, how well, and under what conditions a product will achieve a given purpose.” Requirements define the functions, performance, and environment of the system under development to a level that can be built:

Does the system do WHAT it is supposed to do? – These are Functional Requirements
How well does the system do its functions? – These are Performance Requirements

DoD Requirements Development Process

The Department of Defense (DoD) requirements process is governed by the Joint Capabilities Integration and Development System (JCIDS) Process. The JCIDS Process identifies the capabilities required by the DoD and develops their functional and performance requirements. The main engineering discipline that develops and controls requirements development is Systems Engineering (SE). Requirements development is Step One: Requirements Analysis of the Systems Engineering Process. The four (4) main requirements documents that are produced on a typical DoD program during a specific Acquisition Phase are:

Requirements Development Steps

There is no set standard way to develop requirements, but they are normally developed following the same basic six (6) steps. These requirements development steps don’t really change depending on which SE model is used. All models are similar in their approach but they just usually depict the step differently graphically. The main model that is used is the Systems Engineering “Vee” where requirements development is depicted on the left side.

Below is a list of the primary six (6) steps of requirements development.

Overview: Requirements Development Steps
Step 1: Gather and Develop Requirements
Step 2: Write and Document Requirements
Step 3: Check Completeness
Step 4: Analyze, Refine, and Decompose Requirements
Step 5: Verify & Validate Requirements
Step 6: Manage Requirements

The first overall step in the Systems Engineering Process is Requirements Analysis, which is where Requirements Development fits in. No matter which model is used, the six basic steps to developing needs don’t change much. All models take a similar method, but they show them in different ways. Here is a list of the six (6) most important steps in developing requirements.

Step 1: Gather & Develop Requirements

The first step is to gather, analyze, and develop requirements from the Concept of Operations (CONOPS), stakeholder needs, objectives, and other external requirements. Once requirements are documented, they are prioritized, de-conflicted, and validated with the stakeholders.

Step 2: Write and Document Requirements

The second step focuses on writing down the functional and performance requirements into the appropriate requirements documents: Initial Capabilities Document (ICD), Capability Development Document (CDD), Capability Production Document (CPD), and System Requirements Document (SRD). Requirements must be documented in order to establish a requirements baseline to start building a system and manage any changes. Requirements can be developed using the Capability Development Tracking and Manager (CDTM) tool for DoD programs.

Step 3: Check Completeness

The third step is to check that a complete set of requirements have been developed and documented that defines all system functions that are needed to satisfy the stakeholder needs with their associated performance, environmental, and other non-functional requirements. Requirement Tracing is a big tool in this step.

Step 4: Analyze, Refine, and Decompose Requirements

Requirements Analysis is the first major step in the Systems Engineering Process. This step examines each requirement to see if it meets the characteristics of a good requirement. Each requirement is then decomposed into a more refined set of requirements that are allocated to sub-systems and documented in the Weapons System Specification (WSS). Newly derived requirements are expected to emerge from this process, which continues until all requirements are defined and analyzed.

Step 5: Verify and Validate Requirements

In step five each requirement must be verified and validated to ensure that these are the correct requirements. This ensures that the requirements meet the overall objective of the system and all stakeholder needs.

Step 6: Manage Requirements

In step six the requirements have been accepted and a baseline is established by the stakeholders. Any changes to the requirements are controlled using a Configuration Management process.

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Updated: 3/14/2024

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