Audit evidence is the information and documentation obtained by the auditor during the audit to draw conclusions and support the audit opinion on the financial statements. It includes accounting records, external confirmations, minutes, and the results of analytical procedures and tests. The evidence must be sufficient (adequate in quantity) and appropriate (reliable and relevant) to provide a reasonable basis for the opinion. The auditor’s professional judgment is central to evaluating its quality. Ultimately, the credibility of the entire audit report hinges on the strength and persuasiveness of the audit evidence gathered.
Essentials of Good Audit Evidence:
- Sufficiency (Quantity of Evidence)
Sufficiency refers to the quantity of audit evidence gathered. It is the measure of how much evidence is necessary to support the auditor’s opinion. The required sufficiency is influenced by the assessed risk of material misstatement (higher risk demands more evidence) and the quality of the evidence itself (higher quality may require less quantity). It is a matter of professional judgment, not mere volume. The auditor must obtain enough relevant evidence to form a reasonable conclusion, ensuring the audit work is neither excessive nor inadequate for the circumstances and risks identified.
- Appropriateness: Relevance
Appropriateness comprises relevance and reliability. Relevance means the evidence must have a logical and direct relationship to the financial statement assertion being tested. For example, to test the existence of inventory, physically inspecting the inventory is relevant; reviewing board minutes is not. Evidence is only useful if it pertains to the specific audit objective (e.g., valuation, completeness, rights and obligations). Irrelevant evidence, no matter how reliable, does not support the audit conclusion and wastes resources. The audit procedures must be designed to gather evidence that directly addresses the assertions.
- Appropriateness: Reliability
Reliability pertains to the dependability or trustworthiness of the evidence. The reliability of evidence is influenced by its source and nature. Generally, evidence is more reliable when it is: obtained from independent external sources (e.g., bank confirmations), generated by a well-functioning internal control system, obtained directly by the auditor (e.g., observation), in original documentary form rather than copies or facsimiles, and from knowledgeable, objective sources. The auditor must critically assess the credibility of the source to determine the weight to give the evidence.
- Timeliness
The timing of when evidence is obtained is crucial. Evidence is most relevant when it relates to the period under audit. For balance sheet accounts (e.g., cash, debt), evidence obtained at or near the period-end date is most persuasive for existence assertions. For income statement accounts, evidence obtained throughout the period may be appropriate. The auditor must consider whether evidence obtained at an interim date remains valid at the period-end and what additional procedures are needed to cover the remaining period, ensuring the evidence is pertinent to the reporting date.
- Objectivity & Verifiability
Good audit evidence should be factual, objective, and free from bias. It should be capable of being verified or corroborated by another competent auditor reaching the same conclusion. Subjective evidence, such as management’s unsupported representations, is weak. Strong evidence is impersonal and documentary, like a signed contract, a third-party confirmation, or a bank statement. The objectivity of the provider is key; evidence from a source independent of the entity carries more weight than internally generated evidence. This quality ensures the evidence is defensible and forms a solid basis for the audit opinion.
Methods of Obtaining Audit Evidence:
Method 1: Inspection of Records or Documents
This method involves examining internal or external records and documents to corroborate financial statement assertions. It includes vouching (tracing from accounting records back to source documents to test for occurrence/validity) and tracing (following from source documents forward to the ledger to test for completeness). The auditor inspects tangible assets to verify existence and condition, and reviews contracts, invoices, and minutes. The reliability of this evidence depends on whether documents are internal or external and their form (original is more reliable than a copy or fax).
Method 2: Inspection of Tangible Assets
This is the physical verification of tangible assets owned by the entity, such as inventory, cash, or property, plant, and equipment. It provides direct, highly reliable evidence for the existence and condition of the assets. For example, observing a physical inventory count or inspecting a major piece of machinery. While powerful for proving existence, it does not provide evidence for ownership (rights and obligations) or valuation. It is often combined with other procedures, such as reviewing title deeds or purchase invoices, to obtain evidence for other relevant assertions.
Method 3: Observation
Observation involves watching a process or procedure being performed by others, such as the client’s inventory counting procedures or the operation of internal controls. It provides evidence about performance and process at a point in time but is limited because the act of being observed may influence behavior. It is primarily useful for gaining an understanding of processes but is not sufficient on its own to conclude that a control operated effectively throughout the entire period. It must be supplemented by other tests to obtain evidence about the continuity of operation.
Method 4: External Confirmation
This is the process of obtaining direct written responses from independent third parties to corroborate specific information. It is a highly reliable form of evidence due to its external and independent nature. Common confirmations include requests to banks for account balances and terms, to customers for receivable balances, and to lawyers for litigation details (legal letters). The reliability is high because it is sourced externally, reducing the risk of client manipulation. Auditors must maintain control over the confirmation process, from preparing the request to receiving the response directly.
Method 5: Recalculation and Reperformance
Recalculation involves checking the mathematical accuracy of documents or records, such as recasting an inventory listing or verifying depreciation calculations. Reperformance involves the auditor independently executing procedures or controls that were originally performed by the client, such as reperforming a bank reconciliation. Both methods provide highly reliable evidence because the auditor is performing the task independently. They are direct tests of the accuracy and proper execution of client processes and are often used to test complex calculations or the operating effectiveness of key controls.
Method 6: Analytical Procedures
These involve evaluating financial information by studying plausible relationships among both financial and non-financial data. They range from simple comparisons (current-year vs. prior-year revenue) to complex modeling using disaggregated data. Analytical procedures are used in planning (risk assessment) and as a substantive test, and are mandatory in the overall review stage. They provide indirect evidence, indicating potential misstatements or areas of risk that require further investigation. Their effectiveness depends on the predictability of relationships, the reliability of the data used, and the precision of the auditor’s expectation.
Method 7: Inquiry
Inquiry involves seeking information from knowledgeable persons inside or outside the entity, both in formal interviews and informal discussions. It is used extensively throughout the audit, from understanding the business to corroborating evidence. However, because it is oral evidence, it is generally not sufficient on its own due to its inherent lack of objectivity. Inquiry must be corroborated with more reliable evidence from other sources. For example, management’s representation about a loan agreement must be supported by inspecting the actual signed loan document to be considered reliable audit evidence.
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