7. When designing the size and structure of an audit sample, auditors should consider the specific
audit objectives, the nature of the population, and the sampling and selection methods. The auditor
should consider the need to involve appropriate specialists in the design and analysis of sampling
methodology.
8. The sampling approach will depend on the purpose of the sample. For compliance testing of
controls, attribute sampling is used typically, where the sampling approach is an event or transaction
(e.g., a control such as an authorization on an invoice). For substantive testing, variable sampling is
used often where the sampling unit is monetary.
9. Given that the population should be the entire set of data from which the auditor wishes to sample
in order to reach a conclusion, the population from which the sample is drawn has to be appropriate
and verified as complete for the specific audit objective.
10. To assist in the effective design of the sample, stratification may be appropriate. Stratification is
the process of segregating a population into homogenous subpopulations explicitly defined so that
each sampling unit can belong to only one subpopulation depending on the criteria used for
stratification