Explain like I'm five · Law/Policy

What is ISO/IEC 25000 (SQuaRE)?

The ISO/IEC 25000 series (SQuaRE), told as a story about the student council's shared checklist for what makes software good.

fast means a good app!I think pretty means a good appeveryone's standard for a "good app" is different

Everyone's standard for a "good app" is different.Without a shared standard, "what's a good app?" gets different answers.

this app is totally great!no, this app isn't goodlooking at the same app, different standards give different verdicts

Without a standard, the same app gets judged differently and people argue.Looking at the same app, different standards give different verdicts.

WHAT MAKES GOOD SOFTWARE (SQuaRE)functional suitability — does the job rightperformance efficiency — fast enoughusability — easy to usereliability — doesn't crashsecurity — protects datamaintainability — easy to fixportability — easy to move to other systemscompatibility — works with other systemsISO/IEC 25000 (SQuaRE) = the shared checklist for what makes software "good"the same standard lets everyone judge in the same language

ISO/IEC 25000 (SQuaRE) is the shared checklist for what makes software good.The same standard lets everyone judge in the same language.

Define quality traitsfunction, performance, security, and more
Write the target levelhow good it must be, set in advance
Measure it in numbersnumbers, not just a feeling
Evaluate against the targetmeasured values are judged against the target
THE FOUR CORE PARTS OF SQuaRE2501n Quality Model — defines what to measure2502n Quality Measurement — how to measure it in numbers2503n Quality Requirements — writing the target level in advance2504n Quality Evaluation — judging it against the targetdefine → measure → require → evaluate, in one chain

The core of the SQuaRE series chains together in four parts.Define → measure → require → evaluate, in one chain.

we judge by the same checklistbut acing every trait takes more time and money than we havea faster app may be a little less polished — you have to choose which quality comes first

Even with a checklist, acing everything is hard.A faster app may be a little less polished — you have to choose which quality comes first.

In one breath

ISO/IEC 25000 (SQuaRE) = a shared checklist that defines "good software" by quality characteristics (8 in the 2011 edition, 9 in 2023), then measures, requires, and evaluates it.

The ISO/IEC 25000 series (SQuaRE — Systems and Software Quality Requirements and Evaluation) is a family of international standards that define, measure, require, and evaluate software quality. The 2501n quality model defines eight characteristics — functional suitability, performance efficiency, compatibility, usability, reliability, security, maintainability, and portability (2011 edition; the 2023 edition renames usability as interaction capability and portability as flexibility, and adds safety, for nine) — while 2502n (measurement), 2503n (requirements), and 2504n (evaluation) provide the process to quantify, compare, and judge them. The series also has 2500n (quality management, with common terms) and an extension range (25050–25099).

When grown-ups say it

SQuaRE
The standard series for good software. The umbrella name for the ISO/IEC 25000-series standards.
Quality Model (ISO 25010)
The list defining the quality characteristics (8 in 2011, 9 in 2023). Defines function, performance, usability, and the rest, one by one.
Quality Measurement (ISO 2502n)
How to measure each trait in numbers. Uses measurable indicators, not just a feeling.
Quality Requirements (ISO 2503n)
The target level written down in advance. Becomes the baseline for evaluation.
Quality Evaluation (ISO 2504n)
The process of comparing target against actual and judging. Falling short means it has to be fixed again.
Usability
How easy something is to use. A 2011-edition characteristic; the 2023 edition calls it interaction capability.
Maintainability
How easy it is to fix later. Matters more the longer software stays in use.
Software Testing
Actually running software to check how it behaves. The process that actually checks SQuaRE's standard. → looking inside, or just reading the outside
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