The Sum of All Fears is a 2002 American spy thriller film directed by Phil Alden Robinson, based on Tom Clancy’s 1991 novel of the same name.


Some reviewers remarked that I should give the ISO/IEC 25000 “Systems and software engineering — Systems and software Quality Requirements and Evaluation (SQuaRE)” some more respect.

Actually, SQuaRE is more a clan than a single standard, it has not even been published in a single source, but is spread across numerous documents.

In my (personal and professional) bubble, the major representative of this clan is definitely ISO/IEC 25010, which is explicitly referenced in the iSAQB Software Architecture Foundation curriculum as an important source for software quality terminology.

Why did I use the strange term clan, instead of the commonly used family: Just read on.

A Clan has Multiple Families

Let’s look at the high-level structure of SQuaRE. The diagram given below is contained in several of the official documents.

high-level structure of ISO 25000 family

You find the following five families (yes, each block 01, 02, 03 etc. contains one or several parts). The official terminology is divisions instead of families, but I think the latter sounds a bit more friendly.

  • ISO/IEC 2500n - Quality Management Division. The International Standards that form this division define all common models, terms and definitions referred to by all other standards from the SQuaRE series.
  • ISO/IEC 2501n - Quality Model Division. The International Standards that form this division present detailed quality models for systems and software product, quality in use and data. Practical guidance on the use of the quality model is also provided.
  • ISO/IEC 2502n - Quality Measurement Division. The International Standards that form this division include a system and software product quality measurement reference model, mathematical definitions of quality measures, and practical guidance for their application.
  • ISO/IEC 2503n - Quality Requirements Division. The International Standard that forms this division helps specifying quality requirements.
  • ISO/IEC 2504n - Quality Evaluation Division. The International Standards that form this division provide requirements, recommendations and guidelines for product evaluation, whether performed by independent evaluators, acquirers or developers. The support for documenting a measure as an Evaluation Module is also presented.
  • ISO/IEC 25050-25099-Extension Division. SQuaRE extension (ISO/IEC 25050 to ISO/IEC 25099) is designated to contain system or software product quality International Standards and/or Technical Reports that address specific application domains or that can be used to complement one or more SQuaRE International Standards.

Now, that looks like a highly structured approach to quality. One small issue, though: You cannot simply order this standard via your favourite bookstore or online shop, but have to order all documents separately. And we haven’t yet talked about documents, but only about families (sorry, divisions).

Let’s dive deeper and find out what we need to buy if we want to read and fully appreciate the sheer beauty of ISO/IEC SQuaRE:

All SQuaRE ISO/IEC Documents

As a courtesy to you, dear readers, I spent a few hours in the ISO/IEC online store, making heavy use of their nice search function. The goal was finding out the current (February 2023) prices of all the SQuaRE documents.

Title Price (CHF)
2500n Quality Management Division  
25000: Guide to SQuaRE 145
25001: Planning and management 92
25002: Quality models overview and usage 61
2501n Quality Model Division  
25010: Product quality model (2011) 145
25011: IT service quality models 124
25012: Data quality model 92
25019: Quality-in-use model 61
2502n Quality Measurement Division  
25020: Quality Measurement Framework 145
25021: Quality measure elements 166
25022: Measurement of quality in use 166
25023: Measurement of system and software product quality 166
25024: Measurement of data quality 166
25025: Measurement of IT service quality 124
2503n Quality Requirements Division  
25030: Quality Requirements Framework 166
2504n Quality Evaluation Division  
25040: Evaluation process 166
25041: Evaluation guides 187
25042: Evaluation modules (not avialable)  
25045: Evaluation module for recoverability 166
25050-25099 Extensions  
25051: Requirements for quality of Ready to Use Software Product 145
25052: Cloud services - Part 1: Quality model 92
25059: Quality model for AI systems 61
======= 2636 CHF

Two thousand six hundred and thirty six Swiss Francs. About the same amount in Euro, some 2860 US-Dollar.

For sure, the highest paywall for PDF documents I’ve ever came across. And no, I did not press the “buy” button to collect all those documents.

Practical Usefulness of SQuaRE

As you might guess by now, I’m currently full of doubt wether the ISO 25000 clan of standards will ever have the chance to broadly succeed in industry, or if it will continue to remain a mistery to most development projects.

I seriously doubt that many organizations are willing to cover the complete expenses. Personally I invested in 25010, which I consider a valuable source, despite its shortcomings.

But still I consider the groundwork of ISO-25010 a valid and helpful resource to avoid lengthy discussions on the meaning of (certain) terms. Hopefully our own site can serve this purpuse in the future. Until then, many people will be refering to the public ISO-25010 collection of terms, and most likely ignoring the potentially valuable additions of all the other documents.