The Fraud Triangle explains the three elements that lead to fraudulent behavior: pressure, opportunity, and rationalization. Internal auditors use this model to identify potential fraud risks during planning and risk assessment stages. Audit sampling plays a vital role in detecting red flags by allowing auditors to examine a portion of transactions for anomalies.

For instance, during an audit of employee reimbursements, the auditor may use sampling to review a selection of travel expense claims. The audit reveals that a few claims lack receipts or exceed policy limits. This may indicate opportunity, where weak controls allow fraud, and possibly pressure, such as financial stress motivating the employee. While not every transaction is tested, sampling helps auditors uncover patterns that may point to wider issues.

By combining the Fraud Triangle with audit sampling, auditors can better detect and investigate fraud risks without having to test every transaction, making the audit more efficient and insightful.