There are many methods that auditors could use to perform audit sampling like random sampling, systematic sampling, haphazard sampling, or block sampling.
The auditor might also use their professional judgment to sampling the items from the total population for testing. The auditor may use their judgment to select the items based on certain criteria like:
- The value of items: this can be the high value or the item that has a low value.
- Specific amount: Auditor might select the items with a specific amount.
- Items that have a special characteristic: For example, any items from suppliers A or to customers B
- Other items based on their target.
An auditor can use their judgment to perform audit sampling only in the condition that they have gained deep knowledge of the entity as well as the targeted population.
The auditor might need to make sure that the items that they select represent the total population. Otherwise, the result that comes out from the sample items will lead to making an incorrect conclusion.
Incorrect sampling procedure might lead to increase the sample risks and subsequently audit risks. Therefore, attention needs to be highly paid when the judgment is involved with audit sampling.