Auditor independence refers to the independence of the internal auditor or of the external auditor from parties that may have a financial interest in the business being audited. Independence requires integrity and an objective approach to the audit process. Under the four guiding principles, an auditor cannot function in the role of management, audit the auditor's own work, serve in an advocacy role for the client or have a mutual or conflicting role with the client. Types of engagements, other than a traditional audit, that require the auditor to be independent are Review Engagements, Related Parties Transactions, and Fraud Investigations. A review engagement requires your accountant to perform limited procedures in order to conclude that the financial statements as a whole are free from material misstatements. When auditors are involved in evaluating transactions between an entity and related parties, independence is essential to prevent conflicts of interest and ensure fair assessments of these transactions. Preparation engagement and Compilation don't require independence, both are non attest services. Non attest services differ from attest engagements because CPA's dont express opinions, conclusions, or findings. They cover a broad range of accounting services, such as financial statement preparation, compilations, cash to accrual conversions, tax return preparation, advisory services, forensic accounting, and more. As it is a non-attest service, the accountant does not have to be independent of the client entity.