Frequently Asked Question

Yes. Assessors have two options when performing PCI DSS testing procedures; they can either: 1) test a representative sample of the population according to the assessor's defined sampling methodology, or 2) test 100% of the given population.

Sampling is not mandatory; it is an option for assessors to facilitate the assessment process when there are large numbers of items in a population being tested. If sampling if not used, 100% of the population must be tested. Where sampling is used, each sample must be a representative selection of all variants of the population and be sufficiently large to provide the assessor with assurance that controls are implemented as expected across the entire population.

The use of sampling for PCI DSS testing procedures has not changed in PCI DSS v4.x. Previously, sampling was mentioned in some, but not all, testing procedures. In PCI DSS v4.x, mention of sampling was removed from all testing procedures for consistency.

When considering whether the use of sampling is appropriate for a particular testing procedure, the assessor should consider the size of the population being tested as well as the overall scope and complexity of the environment.

For more information, see PCI DSS v4.x Section 6, For Assessors: Sampling for PCI DSS Assessments.