Content

1. Overview
2. Quality Requirements
   1. FURPS+
   2. ISO Model
3. Testable Quality Requirements

Overview

Not well captured individual requirements, better to be grouped separately requirements, quality requirements.

Part of it are non-functional requirements, part of it are system-wide functional requirements (logging, online help, printing...).

Quality Requirements

Specify how to assess each category in measurable terms.

FURPS+

• Functionality
  • Capabilities, security, reusability
• Usability
  • Human factors, consistency and predictability in the UI, overall aesthetics, end-user documentation, on-line help
• Reliability
  • Frequency and severity of failure, failure recovery, predictability, accuracy, mean time to failure
• Performance
  • Speed, response time, resource consumption, throughput, efficiency
• Supportability
  • Testability, extensibility, maintainability, adaptability, configurability, compatibility, serviceability, installability, internationalization
• +
  • Details of required reports
  • Development constraints (process, tools, etc.)
  • Design, implementation, interface constraints
  • Internationalization concerns (units, languages, ...)
  • Standards to be adhered to
  • Licensing issues
  • Legal concerns
  • Packaging
  • Operational concerns
  • Backups, exception handling
  • Application - specific business rules
  • References to sources of domain information

ISO Model

Testable Quality Requirements

Quantitative statements to verify performance behavior.

• Stakeholders sometimes not able to state their requirements in quantitative terms; can be vague, but every should know it's not verifiable
  • No suitable metrics
  • Cannot relate to the metrics
  • Cost of verification too high
• Conflicts and tradeoffs for different characteristics; try to define priority