Non-Functional Requirements
Non-functional requirements (NFRs) are the qualities and constraints that define how a system should operate rather than what it should do. They are crucial for ensuring a system’s overall quality, usability, and success.
Here are some common types of non-functional requirements:
Performance
- Response time: How quickly does the system respond to user input?
- Throughput: How much work can the system handle in a given time?
- Scalability: Can the system handle increased load or data volume?
Reliability
- Availability: How often is the system accessible?
- Accuracy: How correct are the system’s outputs?
- Consistency: Does the system produce consistent results?
Usability
- Ease of use: Is the system intuitive and easy to learn?
- Efficiency: Can users accomplish tasks quickly and accurately?
- Accessibility: Can users with disabilities use the system?
Security
- Confidentiality: Can unauthorized users access sensitive data?
- Integrity: Can data be modified or corrupted?
- Availability: Can the system be denied access or service?
Maintainability
- Modifiability: Can the system be easily changed?
- Testability: Can the system be easily tested?
- Portability: Can the system be easily moved to a different platform?
Other NFRs
- Compatibility: Can the system interoperate with other systems?
- Localization: Can the system be adapted to different languages and cultures?
- Regulatory compliance: Does the system meet relevant laws and regulations?
Example: A healthcare system might have the following NFRs:
- Performance: Must be able to process patient records in real-time.
- Security: Must protect patient data from unauthorized access.
- Reliability: Must have a high availability rate to ensure continuous service.
- Usability: Must be easy for healthcare providers to use.
By carefully considering these NFRs, system designers can create systems that are not only functional but also meet the needs and expectations of users.