Audit sampling is a fundamental technique used by auditors when it's not practical or necessary to examine every single item in a population. Instead of checking one hundred percent of items, auditors select a representative sample that allows them to draw reasonable conclusions about the entire population while maintaining audit efficiency.
There are two main types of audit sampling. Statistical sampling uses probability theory and mathematical methods to quantify sampling risk and provide measurable confidence levels. Non-statistical sampling relies on the auditor's professional judgment and experience, without mathematical measurement of sampling risk.
The audit sampling process involves several key steps. First, planning the sample by defining objectives, identifying the population, and determining the sampling unit. Second, determining the appropriate sample size based on desired confidence level, tolerable error, and expected error rate. Third, selecting the sample using methods that give each item an equal chance of selection.
After selecting the sample, auditors perform the planned audit procedures on each selected item and document their findings. The next step is evaluating the sample results by analyzing the findings and projecting them to the entire population while assessing sampling risk. Finally, all procedures, results, and conclusions must be thoroughly documented to support the audit opinion.
To summarize what we've learned about audit sampling: It's a technique that allows auditors to test less than one hundred percent of items while still drawing reasonable conclusions. There are two main types, statistical and non-statistical sampling. The process involves six key steps from planning to documentation. Audit sampling is an essential tool that makes auditing both efficient and effective.