Software has a new quality standard: ISO 25010

You might have missed the news that the ISO 9126 quality standard has been replaced recently by the ISO 25010 quality standard. Since the ISO/IEC wants at least 110 euro's for a PDF containing the new standard (WTF????), I thought I'd summarize the new standard and compare it to the old one.

The 'old' ISO 9126 model described six main characteristics, with a set of subcharacteristics:

1. Functionality - A set of attributes that bear on the existence of a set of functions and their specified properties. The functions are those that satisfy stated or implied needs.
   • Suitability
   • Accuracy
   • Interoperability
   • Security
   • Functionality Compliance
2. Reliability - A set of attributes that bear on the capability of software to maintain its level of performance under stated conditions for a stated period of time.
   • Maturity
   • Fault Tolerance
   • Recoverability
   • Reliability Compliance
3. Usability - A set of attributes that bear on the effort needed for use, and on the individual assessment of such use, by a stated or implied set of users.
   • Understandability
   • Learnability
   • Operability
   • Attractiveness
   • Usability Compliance
4. Efficiency - A set of attributes that bear on the relationship between the level of performance of the software and the amount of resources used, under stated conditions.
   • Time Behaviour
   • Resource Utilisation
   • Efficiency Compliance
5. Maintainability - A set of attributes that bear on the effort needed to make specified modifications.
   • Analyzability
   • Changeability
   • Stability
   • Testability
   • Maintainability Compliance
6. Maintainability - A set of attributes that bear on the effort needed to make specified modifications.
   • Analyzability
   • Changeability
   • Stability
   • Testability
   • Maintainability Compliance
7. Portability - A set of attributes that bear on the ability of software to be transferred from one environment to another.
   • Adaptability
   • Installability
   • Co-Existence
   • Replaceability
   • Portability Compliance

The new model has eight characteristics, instead of six, which are quite similar to the old model:

1. Functional suitability - The degree to which the product provides functions that meet stated and implied needs when the product is used under specified conditions
   • Suitability
   • Accuracy
   • Interoperability
   • Security
   • Compliance
2. Reliability - The degree to which a system or component performs specified functions under specified conditions for a specified period of time.
   • Maturity
   • Fault Tolerance
   • Recoverability
   • Compliance
3. Operability - The degree to which the product has attributes that enable it to be understood, learned, used and attractive to the user, when used under specified conditions
   • Appropriateness
   • Recognisability
   • Ease of use
   • Learnability
   • Attractiveness
   • Technical accessibility
   • Compliance
4. Performance efficiency - The performance relative to the amount of resources used under stated conditions
   • Time Behaviour
   • Resource Utilisation
   • Compliance
5. Security - The degree of protection of information and data so that unauthorized persons or systems cannot read or modify them and authorized persons or systems are not denied access to them
   • Confidentiality
   • Integrity
   • Non-repudiation
   • Accountability
   • Authenticity
   • Compliance
6. Compatibility - The degree to which two or more systems or components can exchange information and/or perform their required functions while sharing the same hardware or software environment
   • Replaceability
   • Co-existence
   • Interoperability
   • Compliance
7. Maintainability - The degree of effectiveness and efficiency with which the product can be modified
   • Modularity
   • Reusability
   • Analyzability
   • Changeability
   • Modification stability
   • Testability
   • Compliance
8. Transferability - The degree to which a system or component can be effectively and efficiently transferred from one hardware, software or other operational or usage environment to another
   • Portability
   • Adaptability
   • Installability
   • Compliance

In the new model, security and compatibility were added as main characteristics. I've always wondered why security wasn't that important for software quality measurement, but now it is. Some subcharacterics were added to the model and a number of them were renamed to more accurate terms. The 25010 quality standard also works a bit different than the 9126 standard. The software product quality model describes the internal and external measures of software quality. Internal measures describe a set of static internal attributes that can be measured. The external measures focuses more on software as a black box and describes external attributes that can be measured.
Besides the software product quality model, the 25010 standard also describes another model, the model of software quality in use:

1. Effectiveness - The accuracy and completeness with which users achieve specified goals
   • Effectiveness
2. Efficiency- The resources expended in relation to the accuracy and completeness with which users achieve goals
   • Efficiency
3. Satisfaction- The degree to which users are satisfied with the experience of using a product in a specified context of use
   • Likability
   • Pleasure
   • Comfort
   • Trust
4. Safety - The degree to which a product or system does not, under specified conditions, lead to a state in which human life, health, property, or the environment is endangered
   • Economic damage risk
   • Health and safety risk
   • Environmental harm risk
5. Usability- The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use
   • Learnability
   • Flexibility
   • Accessability
   • Context conformity

I like the fact they've created a seperate model to emphasize how important quality in use is for a software product. Their motivation to do so might be different, they probably assume the characteristics in this model are "in the eye of the beholder" and thus harder to measure. And harder to agree on a common standard for these characteristics.

To summon it up, the new model has a broader range and is more accurate. I believe this is an improvement to the old model, but why someone would pay more than 100 euro's to be able to study the new model is beyond me.