ISO 25010 Quality Characteristics Tree¶

1. Functional Suitability¶

The degree to which a product or system provides functions that meet stated and implied needs when used under specified conditions.

Sub-characteristics¶

Functional Completeness: The degree to which the set of functions covers all the specified tasks and user objectives.
Functional Correctness: The degree to which a product or system provides the correct results with the needed degree of precision.
Functional Appropriateness: The degree to which the functions facilitate the accomplishment of specified tasks and objectives.

Example Quality Scenario¶

When a guest requests trail directions (stimulus), the Trail API (artifact) returns a route that accounts for current trail closures and conditions (response) with 100% accuracy against the current trail status database (measure), under normal operating conditions (environment).

2. Performance Efficiency¶

The performance relative to the amount of resources used under stated conditions.

Sub-characteristics¶

Time Behavior: The degree to which response and processing times meet requirements.
Resource Utilization: The degree to which the amounts and types of resources used meet requirements.
Capacity: The degree to which the maximum limits of a product or system parameter meet requirements.

Example Quality Scenario¶

During peak park hours (environment), when 10,000 concurrent users request trail availability (stimulus), the Trail API (artifact) responds within 200ms at the 95^th percentile (response measure) without exceeding 70% CPU utilization on the allocated infrastructure (resource measure).

3. Compatibility¶

The degree to which a product, system, or component can exchange information with other products, systems, or components and perform its required functions while sharing the same hardware or software environment.

Sub-characteristics¶

Co-existence: The degree to which a product can perform its functions efficiently while sharing a common environment and resources with other products without adverse impact.
Interoperability: The degree to which two or more systems, products, or components can exchange and use information.

Example Quality Scenario¶

When the Trail Management System is deployed alongside the Reservation System on the same Kubernetes cluster (environment), both systems (artifact) maintain their SLA response times (response) with no more than 5% performance degradation compared to isolated deployment (measure).

4. Usability¶

The degree to which a product or system can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.

Sub-characteristics¶

Appropriateness Recognizability: The degree to which users can recognize whether a product or system is appropriate for their needs.
Learnability: The degree to which a product or system can be used by specified users to achieve specified goals of learning with effectiveness, efficiency, freedom from risk, and satisfaction.
Operability: The degree to which a product or system has attributes that make it easy to operate and control.
User Error Protection: The degree to which a system protects users against making errors.
User Interface Aesthetics: The degree to which a user interface enables pleasing and satisfying interaction.
Accessibility: The degree to which a product or system can be used by people with the widest range of characteristics and capabilities.

Example Quality Scenario¶

A new park operator (source) using the trail management dashboard for the first time (stimulus) can successfully close a trail and notify affected guests (response) within 5 minutes without prior training (measure), using only the dashboard interface (environment).

5. Reliability¶

The degree to which a system, product, or component performs specified functions under specified conditions for a specified period of time.

Sub-characteristics¶

Maturity: The degree to which a system, product, or component meets needs for reliability under normal operation.
Availability: The degree to which a system, product, or component is operational and accessible when required for use.
Fault Tolerance: The degree to which a system, product, or component operates as intended despite the presence of hardware or software faults.
Recoverability: The degree to which a product or system can re-establish the desired state of performance and recover the data directly affected in the event of an interruption or failure.

Example Quality Scenario¶

When the primary database becomes unavailable (stimulus), the Trail API (artifact) continues serving read requests from the replica (response) with no more than 5 seconds of degraded service (measure), during peak operating hours (environment).

6. Security¶

The degree to which a product or system protects information and data so that persons or other products or systems have the degree of data access appropriate to their types and levels of authorization.

Sub-characteristics¶

Confidentiality: The degree to which a product or system ensures that data are accessible only to those authorized to have access.
Integrity: The degree to which a system, product, or component prevents unauthorized access to, or modification of, computer programs or data.
Non-repudiation: The degree to which actions or events can be proven to have taken place so that they cannot be repudiated later.
Accountability: The degree to which the actions of an entity can be traced uniquely to that entity.
Authenticity: The degree to which the identity of a subject or resource can be proved to be the one claimed.

Example Quality Scenario¶

When an unauthorized user attempts to access the trail management admin API (stimulus), the system (artifact) rejects the request with a 401 response (response) and logs the attempt with source IP, timestamp, and attempted resource (measure) within all environments (environment).

7. Maintainability¶

The degree of effectiveness and efficiency with which a product or system can be modified to improve it, correct it, or adapt it to changes in environment and requirements.

Sub-characteristics¶

Modularity: The degree to which a system or computer program is composed of discrete components such that a change to one component has minimal impact on other components.
Reusability: The degree to which an asset can be used in more than one system or in building other assets.
Analysability: The degree of effectiveness and efficiency with which it is possible to assess the impact of an intended change, diagnose deficiencies or causes of failures, or identify parts to be modified.
Modifiability: The degree to which a product or system can be effectively and efficiently modified without introducing defects or degrading existing product quality.
Testability: The degree of effectiveness and efficiency with which test criteria can be established and tests can be performed to determine whether those criteria have been met.

Example Quality Scenario¶

When a developer needs to add a new trail attribute (stimulus), the change (response) requires modifications to no more than 3 files in the Trail API (artifact) and can be completed, tested, and deployed within 4 hours (measure), in the standard development environment (environment).

8. Portability¶

The degree of effectiveness and efficiency with which a system, product, or component can be transferred from one hardware, software, or other operational or usage environment to another.

Sub-characteristics¶

Adaptability: The degree to which a product or system can effectively and efficiently be adapted for different or evolving hardware, software, or other operational or usage environments.
Installability: The degree of effectiveness and efficiency with which a product or system can be successfully installed and/or uninstalled in a specified environment.
Replaceability: The degree to which a product can replace another specified software product for the same purpose in the same environment.

Example Quality Scenario¶

When the Trail API needs to be migrated from AWS EKS to Azure AKS (stimulus), the containerized application (artifact) deploys successfully (response) with only infrastructure configuration changes (no code modifications) within 2 business days (measure), including CI/CD pipeline adjustments (environment).