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Information-technology systems have to meet required, desired and expected quality requirements. Therefore, development teams need such requirements in concrete, specific and operationalized ways. The current quality standards, like ISO-25010, lack practical guidance and pragmatism, therefore we propose a usable and simple alternative:
The arc42 quality model Q42 (pronounced “Kju-Fortytwo” or “Kju-Four-Two”) is a simple, pragmatic yet effective approach to product and system quality. It starts with stakeholders’ expectations and requirements. From these, it derives 8 important system properties, which are sufficient to cover most, if not all, required, desirable or expected of the more than 100 traditional qualities.
Find out more in our introduction to the Q42 quality model
On this site you find:
Qualities and example-requirements are organized along the following top-level properties (attributes or tags), and cross-referenced. A single quality attribute (like “availability”) might have multiple properties (#reliable, #usable and #safe, in this case).
| Top-level property | Explanation |
|---|---|
| #reliable (70) | Perform specified functions under specified conditions without interruptions or failures |
| #flexible (42) | Serve a different or expanded set of requirements, the ease with which the product can be adapted to changes in its requirements, contexts of use, or system environment. Synonyms: modifiable, adjustable, changeable, versatile |
| #efficient (65) | Perform functions within specified time, capacity and throughput parameters, using appropriate resources (like memory, network bandwith, threads) |
| #usable (91) | Enable users to perform their tasks safely, effectively and efficiently while enjoying the experience |
| #safe (14) | Avoid states in which human life, health, property or the environment is endangered, detects and warns of risks and hazards. |
| #secure (29) | Protect information and data so that persons or other products have only access to an extend appropriate to their types and levels, and to defend against attack patterns by malicious actors |
| #suitable (41) | An abstract property, applicable to various objects. Provide properties that meet stated and implied needs of intended stakeholders. |
| #operable (47) | Easy to deploy, operate, monitor and control |