Step 4 – Executing the Plan

During the examination phase of a performance audit, the auditors conduct the procedures they have described in their audit plans, including sampling procedures, and document the results of these procedures. However, in some cases, it may be impossible to implement the sampling procedures exactly as planned and then the auditors need to modify the plan to adjust to the circumstances.

Revising the Plan as Needed

The execution of a sampling plan, however well conceived and sound, always requires exercising professional judgment. New information on a sample’s parameters can always be brought to the auditors’ attention during the audit, and this information could affect the sample’s size and reliability. New information can be obstacles to properly implementing the planned audit procedures, which may require modifying or abandoning them. Auditors should also be vigilant when they cannot examine some selected items. If a selected item is missing and it cannot be determined what happened to it, it should normally be considered a deviation.

In a generalizable sample, auditors must monitor the items as they are selected and analyzed and note all observed deviations. If the observed error or deviation rate is higher than the auditors planned for, this indicates that the sample size may not be large enough to render reliable conclusions (since the expected error rate is one factor influencing sample size). It could also mean that the information collected cannot be relied on and the sampling should be stopped. In both cases, changes to the sampling plan may be necessary.

For purposeful sampling, auditors may need to rethink the selection criteria based on whether or not the selected items are relevant to the particular investigation required by the audit. For example, if an audit aims to examine controls around both sole source and competitive procurements and the auditors take a purposeful sample of the highest value procurements, but soon find that their sample does not include many (or any) sole source procurements, then their efforts will be of limited value. In such a case, the auditors would have to rethink their sample. (One option could be to take a sample of high-value competitive procurements and a separate sample of sole source procurements.)

• PreviousKey Elements of a Sampling Plan – Purposeful Sampling
• NextDocumenting the Plan and Its Results