Usability

Regulators care about usability to the extent it affects safety and performance, not comfort alone. Good usability reduces use errors, which is why usability engineering feeds the risk management file.

characteristic of the USER INTERFACE that facilitates use and thereby establishes EFFECTIVENESS, EFFICIENCY and USER satisfaction in the intended USE ENVIRONMENT Note 1 to entry: All aspects of USABILITY, including EFFECTIVENESS, EFFICIENCY and USER satisfaction, can either increase or decrease SAFETY.

IEC 62366-1:2015+AMD1:2020, clause 3.16

For the purpose of this document, usability refers to the characteristic of the user interface that establishes effectiveness, efficiency and ease of user learning and user satisfaction.

MDCG 2020-1, Section 3.3, Definitions

Characteristic of the user interface that facilitates use and thereby establishes effectiveness, efficiency and user satisfaction in the intended use environment. Note 1 to entry: all aspects of usability, including effectiveness, efficiency and user satisfaction, can either increase or decrease safety.

MDCG 2022-2, Section 4, Definitions (source: IEC 62366:2015)

Usability is defined as the characteristic of the user interface that establishes effectiveness, efficiency, ease of user learning and user satisfaction in the intended use environment (section 3.16) o Note 1 to entry: All aspects of usability, including effectiveness, efficiency and user satisfaction, can either increase or decrease safety of a medical device.

MDCG 2021-6 Rev.1, Question 17 (quoting EN 62366-1)

MDCG 2021-6 and MDCG 2022-2 tie usability to the intended use environment and note that every aspect of it can increase or decrease safety. MDCG 2020-1 gives a shorter definition for its own purposes without those additions.