ISO IEC 24570-2018 PDF

Full title and description

ISO/IEC 24570:2018 — Software engineering — NESMA functional size measurement method — Definitions and counting guidelines for the application of Function Point Analysis. This International Standard defines the NESMA (Netherlands Software Metrics Association) variant of Function Point Analysis (FPA), providing definitions, counting rules and guidance for measuring the functional size of software using the NESMA method.

Abstract

ISO/IEC 24570:2018 specifies a consistent set of definitions, rules and counting guidelines to apply the NESMA functional size measurement method (a recognized FPA/Function Point Analysis approach). The standard describes how to identify and count the five primary function types, determine boundaries and complexity, and produce repeatable functional size measurements that are technology-independent and suitable for estimation, benchmarking and productivity analysis.

General information

• Status: Published (confirmed on review).
• Publication date: 25 January 2018 (Edition 2, 2018).
• Publisher: ISO/IEC (technical work by ISO/IEC JTC 1 / SC 7).
• ICS / categories: 35.080 (Software engineering / Software development and documentation).
• Edition / version: Edition 2 (2018).
• Number of pages: 70.

Scope

ISO/IEC 24570:2018 specifies the definitions, counting rules and guidelines required to apply the NESMA Function Point Analysis method to measure functional size of software. It covers identification of functional user requirements suitable for sizing, the classification and counting of the five function types (Internal Logical Files, External Interface Files, External Inputs, External Outputs and External Inquiries), rules for determining boundaries and complexity, and guidance to ensure repeatable, comparable measurements across projects and organizations.

Key topics and requirements

• Definitions of NESMA terminology and functional size concepts.
• Counting rules for the five function types: ILF (Internal Logical File), EIF (External Interface File), EI (External Input), EO (External Output) and EQ (External Inquiry).
• Guidance for setting system/application boundaries and identifying transactional vs. data functions.
• Complexity rules and weighting conventions to convert counts into function points.
• Rules for handling special cases (e.g., screens, reports, interfaces, batch processes, reused components).
• Procedures to ensure consistent counting across analysts and projects (traceability and documentation of counts).
• Recommendations for applying NESMA counts to estimation, benchmarking, contract sizing and productivity measurement.

Typical use and users

Used by software metrics specialists, project managers, estimators, quality and process improvement teams, procurement officers and vendors who need a repeatable, standards-based measure of functional software size. Typical applications include project estimation and planning, vendor bidding and contract sizing, productivity and quality benchmarking, release and scope management, and historical performance analysis.

Related standards

ISO/IEC 24570:2018 is part of the family of functional size measurement standards. Commonly referenced related standards include ISO/IEC 20926 (IFPUG functional size measurement method), the ISO/IEC 14143 series (functional size measurement reference model and parts), and standards/methods for non-functional sizing such as IEEE 2430 (SNAP) and subsequent international publications addressing non-functional size measurement. ISO/IEC 24570:2018 replaces ISO/IEC 24570:2005.

Keywords

NESMA, Function Point Analysis, FPA, functional size measurement, function points, ILF, EIF, EI, EO, EQ, software metrics, ISO/IEC JTC 1, software estimation, benchmarking, counting guidelines.

FAQ

Q: What is this standard?

A: ISO/IEC 24570:2018 is an international standard that specifies the NESMA Function Point Analysis method's definitions and counting guidelines for measuring the functional size of software.

Q: What does it cover?

A: It covers the terminology, identification and counting rules for the five function types (ILF, EIF, EI, EO, EQ), boundary and complexity rules, special-case handling, and guidance to produce consistent, repeatable function point counts for estimation and benchmarking.

Q: Who typically uses it?

A: Software metrics analysts, estimators, project managers, procurement and vendor teams, and organizations performing benchmarking, productivity analysis or contract sizing use this standard.

Q: Is it current or superseded?

A: ISO/IEC 24570:2018 replaced the 2005 edition. The 2018 edition is the current NESMA FPA international standard (it has been through ISO's periodic review process and remains the applicable edition unless a newer revision is published).

Q: Is it part of a series?

A: Yes — it belongs to the broader set of functional size measurement documents and standards (for example, ISO/IEC 14143 reference documents and ISO/IEC 20926 for the IFPUG method). These complementary standards together provide reference models, method-specific counting practices and guidance for functional and non-functional sizing.

Q: What are the key keywords?

A: NESMA, Function Point Analysis, functional size measurement, function points, ILF, EIF, EI, EO, EQ, counting rules, software metrics, estimation, benchmarking.