Metrics

Metrics in MoSy are measurable indicators of how well a system fulfills the Key Objectives defined in the High-Level System View. While Key Objectives describe what each actor wants to achieve when interacting with the system, Metrics provide quantitative ways to track progress and assess system performance at a more granular level.

A well-defined Metric ensures that system flows are not just implemented but also optimized to deliver real value. By continuously monitoring these metrics, teams can identify bottlenecks, inefficiencies, and opportunities for improvement.

Actor	Key Objective	Metrics
Customer	Seamless checkout experience	- Cart abandonment rate - Checkout completion time
Supplier	Ensure timely and accurate inventory replenishment	- On-Time Stock Replenishment Rate - Inventory Turnover Ratio
E-commerce system	Fast, secure, and reliable experience	Average Transaction Processing Time

Each Metric must be linked to a Key Objective since they’ll drive the system’s behavior. This guarantees a complete alignment with the business objectives at the Flow level.

There are multiple Metric types, amongst them:

• Business Metrics: Measure success in alignment with key objectives. (e.g., Customer Retention Rate, Revenue per Transaction).
• Performance Metrics: Measure system efficiency and responsiveness. (e.g., Average API Response Time, Order Processing Time).
• Engagement Metrics: Track user behavior and system adoption. (e.g., Checkout Completion Rate, Feature Usage Rate).
• Reliability Metrics: Ensure system uptime and operational stability. (e.g., System Availability, Failed Payment Rate).

Metrics in Mosy are shown in pink and aligned with the actions and system entities they refer to. Metrics should always be based on existing entities; otherwise, you cannot calculate them. Sometimes, adding metrics can lead your group discussion to create new entities solely for modeling concepts and obtaining data that you can later use as metrics. You can include a descriptive note explaining how the metric is calculated based on the system entities.

Actions identified as enablers of the key objectives should have associated metrics in the same vertical, using its available system entities. These metrics allow you to measure how well your flow delivers on an actor’s goal.

Metrics in MoSy

The Non-functionals Challenge in IT Businesses

From the multiple metric types, non-business metrics, such as reliability, security, scalability, and performance, often lack a direct link to business objectives because non-functional requirements (NFRs) are frequently neglected in high-level business planning. However, these metrics are critical to delivering the expected value and enabling the system to function correctly. While customers and stakeholders may not explicitly request “high availability” or “low latency,” these factors directly impact user satisfaction, trust, and long-term adoption.

There are multiple reasons why NFRs are usually overlooked when defining business value:

• They are assumed rather than explicitly defined

  • Business objectives focus on market success, revenue, and engagement but rarely articulate expectations like 99.99% uptime or latency below 200ms.
  • Everyone expects a reliable and secure system, so it’s rarely a differentiating factor—until it fails.

• They don’t map easily to revenue or direct user value

  • A well-optimized API response time improves user experience, but it may not be immediately apparent how much it impacts revenue growth.
  • Security measures reduce risk exposure, but businesses often invest only after an incident happens.

• They are considered “supporting enablers” rather than core value drivers

  • Business leaders prioritize features over infrastructure improvements, delaying investments in non-functional enhancements.

To bridge this gap, MoSy provides a structured way to link non-functional metrics to key objectives by recognizing that:

• The system itself is an actor with operational excellence as a key objective.
• Non-functional aspects directly impact business success even if they aren’t explicitly stated in business goals.

Again, MoSy ensures a good discussion between business, product, and technology and provides a common alignment on the expected level of availability, security, performance, etc., required. This discussion also works the other way around, guaranteeing the system isn’t technically better than needed.

In summary, the solution is to expand the Key Objectives for the System Actor to include non-functional Goals explicitly agreed upon across the different roles in the organization. For the e-commerce system to meet its Key Objective of “Fast, secure, and reliable experience,” it’s worth adding metrics such as System Availability and API Response Time and agreeing on reasonable targets with the business team.

A comprehensive overview of the Customer Purchase Flow, including metrics.