* Independence and objectivity are fundamental to effective internal audits. Including individuals from the audited department creates a conflict of interest and compromises the audit's impartiality.
* While familiarity with the department's processes is beneficial, auditors should come from outside the department to provide a fresh, unbiased perspective.
* Including managers (C) or higher-level executives (D) can introduce intimidation and pressure on the auditors, undermining the audit's integrity.
References:
* ASQ CMQ/OE Handbook, Section VI: Quality Systems (discussions on internal audits, auditor independence, and objectivity)