The responsibility for defining the scope of an assessment lies with client management. The organization undergoing the assessment must identify which systems, applications, facilities, and business units are in scope. This decision is based on business objectives, regulatory requirements, contractual obligations, and the sensitivity of data being processed. External Assessors play a supporting role by reviewing scope decisions and ensuring they are reasonable and sufficient to meet assurance objectives. HITRUST does not define scope directly but requires that scope decisions be documented and defensible. An accurately defined scope ensures that the assessment reflects the organization’s risk exposure without omitting critical components. Mis-scoping can either undermine assurance or create unnecessary testing burden.