User-System Model

A conceptual model that describes the relationship between a user and the technology system they interact with, taking into account the user's abilities, preferences, and needs alongside the system's capabilities, interfaces, and constraints. In accessibility engineering, user-system models are essential for understanding how different users with varying abilities interact with technology and where breakdowns in interaction may occur. The model helps identify the gap between what a system requires of a user (such as visual acuity, motor precision, or cognitive load) and what the user can provide, highlighting where assistive technology, interface adaptation, or design changes are needed to bridge that gap.