Efficiency

Time, effort and steps all count as resources. Efficiency matters for safety when a slow or cumbersome task leads users to take shortcuts.

resources expended in relation to EFFECTIVENESS [SOURCE: ISO 9241-11:1988, 3.3, modified – the term "EFFECTIVENESS" has replaced the original phrase, which here constitutes the definition of 3.4 EFFECTIVENESS.

IEC 62366-1:2015+AMD1:2020, clause 3.5