By prioritizing usability, organizations can:
According to ISO 9241-11:2018, usability is defined as:
The International Organization for Standardization’s (ISO) revision of in 2018 was not merely an administrative update; it was a necessary paradigm shift. By updating the definition of usability, the standard successfully bridged the gap between rigid 1990s ergonomics and the modern, holistic field of User Experience (UX) design. iso 9241-11 usability definition 2018
This subtle pivot shifts the designer’s focus from "building a better button" to "designing a better interaction flow." It acknowledges that a product cannot be inherently "usable" if the environment, the user’s prior knowledge, or the specific task does not align with the design.
| Aspect | 1998 Version | 2018 Version | |--------|--------------|----------------| | | Focused on product’s “ease of use” | Focused on outcomes of use in a specific context | | Satisfaction | Vaguely defined | Clarified: freedom from discomfort and positive attitudes | | Context | Implied | Explicitly required for any usability claim | | Applicability | Primarily software interfaces | All products, systems, services (physical, digital, mixed) | | Measurement | Brief examples | More detailed guidance on measurement methods (including subjective, objective, and performance metrics) | | Aspect | 1998 Version | 2018 Version
. If she accidentally logs it under the wrong patient because the UI is cluttered, it fails this pillar. 2. Efficiency (How much effort does it take?) In an emergency, every second is a resource. If the app requires Sarah to navigate through five different screens to find the medication list, she is wasting mental and physical energy. The Result: The team redesigned the interface so the most critical life-saving data is one tap away. By reducing the time taken from 60 seconds to 12 seconds, they increased
One cannot claim “Product X is usable.” Instead, one must claim: “For novice users, performing an online purchase in a noisy home environment, the product achieves 98% task completion (effectiveness), average 2 minutes per task (efficiency), and a SUS score of 85 (satisfaction).” Efficiency (How much effort does it take
The ISO 9241-11 standard identifies three key aspects of usability:
(“Ergonomics of human-system interaction — Part 11: Usability: Definitions and concepts”) replaces the earlier 1998 version. It provides an updated, internationally standardized framework for defining and understanding usability in system, product, or service design. The standard shifts from a narrow “ease of use” perspective to a broader, context-dependent definition that emphasizes outcomes of use (effectiveness, efficiency, satisfaction) within specific contexts of use .
The ISO 9241-11:2018 standard defines usability as: