What it asks for. The organisation must select appropriate assessors, develop a control assessment plan, assess controls at a defined frequency to see whether they are implemented correctly and producing the desired outcome, produce an assessment report and share the results with designated people.
In practice. Doing this well means a planned programme of control testing, using internal audit, independent assessors or automated checks, with documented test procedures, evidence gathered and findings rated and tracked. Auditors expect the assessment plan, reports, remediation plans and management responses. This aligns with internal audit expectations in ISO/IEC 27001 clause 9.
Common gaps. Assessments often check that a control is documented rather than whether it works. Findings tend to be carried over from one cycle to the next without resolution.