Overview
ISO/IEC 24570:2018 - "Software engineering - NESMA functional size measurement method - Definitions and counting guidelines for the application of function point analysis" defines the NESMA (Netherlands Software Metrics Association) variant of Function Point Analysis (FPA). The standard specifies the definitions, rules and counting guidelines needed to measure functional size consistently across applications and projects. It is a second-edition, normative reference for organizations applying NESMA FPA to estimate size, effort, productivity and to support benchmarking and contract measurement.
Key Topics
The standard provides detailed guidance and rule sets on:
- FPA concepts and rationale - purpose, types of analyses (indicative, high-level, detailed) and when to apply each.
- Scope and application boundary - how to define the application or project boundary for counting.
- Function types and valuation - transactional functions (inputs, outputs, enquiries) and data functions (internal logical files, external logical files).
- Counting rules - step-by-step plan, complexity assessment, data element types (DET), and completeness checks.
- Special situations - packaged software, screens/windows, report and query facilities, prototyping and replacement scenarios.
- Data modeling guidance - deriving logical files from normalized models, denormalization rules, and shared data use.
- Project vs application sizing - measuring functional size for development, enhancement and rebuild projects.
- Normative annexes such as a summary of features for valuing function types and a glossary.
Applications
ISO/IEC 24570:2018 is used to:
- Produce consistent functional size measurements (function points) for estimation and costing.
- Support project planning, productivity analysis, benchmarking and performance metrics.
- Define objective size metrics in contracts, SLAs, and portfolio management.
- Assess scope and impact during enhancements, replacements or reengineering.
- Enable traceable counting across lifecycle phases (requirements, analysis, design, construction, maintenance).
Who Should Use It
- Software estimators and project managers for effort/cost estimates.
- IT finance and procurement for vendor contracts and benchmarking.
- Quality assurance and measurement teams for consistent sizing and metrics.
- Consultants and auditors performing functional size validation.
- Organizations adopting NESMA FPA for internal governance and reporting.
Related Standards
ISO/IEC 24570 complements other software measurement and functional size methods. Organizations often use it alongside internal measurement policies and other ISO/IEC guidance on software engineering and metrics.
Keywords: ISO/IEC 24570:2018, NESMA, function point analysis, FPA, functional size measurement, counting guidelines, software engineering, function points.
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