A requirement is an attribute of a product, service or system necessary to produce an outcome(s) that satisfies the needs of a person, group or organization. Operational Requirements are capabilities, performance measurement (Measures of Effectiveness, Measures of Performance, Measures of Suitability & Technical Performance Measurements), and processes needed to address mission area deficiencies, evolving threats, emerging technologies, or weapon system cost improvements. They are developed and validated by the user and listed in the Capability Development Document (CDD) and Capability Production Document (CPD). They form the foundation for weapon system technical specifications, contract requirements, and guide product development so that solutions specifications actively solve the stated problems. See Requirement Types
Definition: Operational requirements are those statements that “identify the essential capabilities, associated requirements, performance measures, and the process or series of actions to be taken in effecting the results that are desired in order to address mission area deficiencies, evolving applications or threats, emerging technologies, or system cost improvements” 
Operational Requirements Development
The assessment of operational requirements starts with the Concept of Operations (CONOPS) and goes to a greater level of detail in identifying mission performance assumptions and constraints and current deficiencies of or enhancements needed for operations and mission success. They are normally developed in the Materiel Solution Analysis (MSA) Phase and Technology Maturation & Risk Reduction (TD) Phase of the Acquisition Process.
Operational Requirements Development Steps
- Overview: Requirements Development Process
- Step 1: Gather & Develop Requirements
- Step 2: Write & Document Requirements
- Step 3: Check Completeness
- Step 4: Analyze, Refine & Decompose Requirements
- Step 5: Verify & Validate Requirements
- Step 6: Manage Requirements
Operational Requirements Questions
The operational requirements focus on how the system will be operated by the users, including interfaces and interoperability with other systems. The requirements establish how well and under what conditions the system must perform. The operational requirements should answer: [1,2]
- Who is asking for this requirement?
- Who needs the requirements?
- What functions must be performed?
- Who will be operating the system?
- Where will the system be used?
- When will the system be required to perform its intended function and for how long?
- How will the system accomplish its objective?
- What functions/capabilities must the system perform?
- What decisions will be made with the system?
- What data/information is needed by the system?
- What are the performance needs that must be met?
- What are the constraints?
- How will the requirements be verified?
- Where will the system be used?
- How will the system accomplish its mission objective?
- What are the critical system parameters to accomplish the mission?
- How are the various system components to be used?
- How effective or efficient must the system be in performing its mission?
- How long will the system be in use by the user?
- What environments will the system be expected to operate in an effective manner?
Operational Requirements Best Practices
There are a number of best practices that should be followed in order to develop the best operational requirements possible. The best practices are:
- Early involvement by all stakeholders in the process
- Be clear and precise
- The simpler the better
- Make sure the user understands them
- Avoid unreasonable expectations
- Every requirement must have a purpose
- Make sure they are achievable
- Make sure they can be traced to the lower level requirements
- The document that defines the proper organization for all armed-forces specifications is MIL-STD-961 “Defense and Program-Unique Specifications Format and Content” – 9 Jan 2014
AcqLinks and References:
-  DAU Systems Engineering Fundamentals Guide
-  Kossiakoff, A., and N. Sweet, 2003, Systems Engineering Principles and Practices, Hoboken, N.J., John Wiley & Sons.
- Space and Missile Systems Center (SMC) Systems Engineering Primer & Handbook
- NASA Systems Engineering Handbook (large 9 Mb file)
- Department of Home Land Security (DHS): Developing Operational Requirements, Nov 2008 (large 14 Mb file)
- MIL-STD-961 “Defense and Program-Unique Specifications Format and Content” – 9 Jan 2014