Clause 5.2: User controllability
User controllability describes how far a user is able to step into how the system behaves, and to do so in time to matter.
What clause 5.2 is
User controllability describes how far a user is able to step into how the system behaves, and to do so in time to matter. The second edition defines a controller as a person or outside agent with authority to act, a control point as the place in the interface where that action lands, and engagement of control as the moment when an authorised party takes charge of a group of control points. It places the characteristic under interaction capability rather than usability.
What the 2023 edition said
The first edition introduced user controllability as a new sub-characteristic of usability and described intervention in a timely manner.
What the second edition changes
The parent changes from usability to interaction capability, following the 2023 base model. The control vocabulary is added, so the intervention has a named actor and a defined point. The characteristic is linked to the controllability work in the AI terminology standard and the newer controllability specification.
The FDIS text is not public. The change line above is read from the public draft, which is not the FDIS and may differ. No clause level diff is invented here. The ISO stage record is the authority for the dates.
Why it matters to the buyer
A user who cannot act is not in control, however good the interface is. The move to interaction capability and the new vocabulary make the requirement testable: who is the controller, where is the control point, and what happens at the moment control is taken.
What to write in the requirement
For each system, name the controller, list the control points and describe the engagement of control. State the time within which intervention must be possible and what the system does while control is being taken. A role without the authority to act is not a controller.
Evidence a reviewer asks for
A reviewer will ask who can stop the system, where, and how quickly. A named committee is not an answer unless it can act.
- Control designA diagram of the control points, the controller for each and the state the system enters when control is taken
- Role and authorityThe role description and delegation that give the controller the authority to act
- Exercise recordA dated record of an intervention being exercised, with what worked and what did not
Where it commonly fails
- The controller is a role with no authority
- Control points are not defined
- The intervention has never been exercised
What to do before publication
Write the controller and control-point list now, then exercise one intervention before publication.
Read across
Source for clause 5.2: ISO/IEC 25059, Clause 5.2, retrieved 20 October 2026. The change line rests on the public draft of the second edition and ISO page 88234. The requirement, evidence and gaps are written from our record. Every source.