Usability is meaningless to discuss apart from users, goals, and context

What it is

A question like "how usable is this app" has no subject and cannot be answered: usability judgments attach to three conditions—who is using it (older adults or fluent young users), doing what (paying by QR code or organizing an album), and where (one-handed in the dark or two-handed at a desk). Change the conditions and the same interface earns opposite verdicts.

Why it happens

Every usability component is defined by the three conditions: "completion" in effectiveness depends on how the goal is set, "expenditure" in efficiency depends on the skills users already have, and "good or bad" in satisfaction depends on expectations in context. Strip the conditions and the terms lose their reference—"fast" relative to whose fluency, "simple" relative to which task structure. An evaluation sentence without a subject is a measurement without a defined scale.

Studying it

The methodological counterpart is to fix the user-goal-context triple in the study design and in the report: conclusions are stated as holding "for users X completing goal Y in context Z." When reviewing prior work, treat any result missing one of the three as uncitable evidence; for every "usability research shows" in a literature review, check whether the triple is stated.

Where it stops holding

"Meaningless" does not forbid comparison: with users, tasks, and context fixed, cross-design comparison stands. Heuristic evaluation does not measure users directly, but its judgments still assume a target user; wrong assumption, failed method. The claim limits the scope of conclusions, not the act of evaluating.

Applying it

• Ban subject-less usability phrasing in requirements, reviews, and test documents; always complete the three conditions.
• When citing competitor or literature evaluations, reconstruct their three conditions first, then decide applicability to your setting.
• When someone says "users find it hard," ask which users, which task, which context; no answer, no evidence.

Related

• Same group: B5.01.1 Usability is the extent to which specific users achieve specific goals in specific contexts · B5.01.3 Usability is a measurable property, not an evaluative adjective
• Nearby: B5.01 Usability Definition · Q1 Research Methods and Evaluation
• Search terms: context of use · user differences · task analysis