Audit sampling is the testing of less than 100% of the items within a population to obtain and evaluate evidence about some characteristic of that population, in order to form a conclusion concerning the population.
“Audit sampling” means the application of audit procedures to less than 100% of the items within an account balance about some characteristic of the items selected in order to form or assist in forming a conclusion concerning the population. It is important to recognise that certain testing procedures do not come within the definition of sampling. Tests performed on 100% of the items within a population do not involve sampling. Likewise, applying audit procedures to all items within a population which have a particular characteristic (for example, all items over a certain amount) does not qualify as audit sampling with respect to the population examined, nor with regard to the population as a whole, since the items were not selected from the total population on a basis that was expected to be representative. Such items might imply some characteristic of the remaining portion of the population but would not necessarily be the basis for a valid conclusion about the remaining portion of the population.
In an audit, sampling procedures are used because it is not practical to examine every single item in a population. For example, the auditor may select an audit sample of non-current assets, and verify their existence, condition and value. It would not be practical for the auditor to track down every single asset on the books. But, if all the items in the audit sample are verified then it may be appropriate to draw the conclusion that all the assets are correctly recorded in the books (assuming the audit sample has been selected correctly and is of sufficient size).