A detailed audit is used to examine a large proportion of the transactions of a business. It is typically used to search for cases of suspected fraud, where there may be a few fraudulent transactions hidden amongst a mass of legitimate transactions. This type of audit may also be used to locate opportunities for cost reductions and process improvements. In these situations, detailed audits are normally conducted by the internal audit staff.
Detailed audits are not commonly used by outside auditors, who instead use a much smaller sample size as part of their auditing activities.