Representative Sampling

In web accessibility auditing, the practice of selecting a subset of pages from a website that statistically reflects the full site, so that evaluation findings can be generalised to pages not directly audited. WCAG-EM requires that a 'representative sample' be included alongside a 'structured sample' of common page types, but it does not specify a probabilistic sampling procedure. Research methodologies such as OPTIMAL-EM attempt to formalise representative sampling by clustering pages by structural similarity and then drawing pages from each cluster — particularly from clusters with high complexity variance, which tend to carry more accessibility barriers. Representative sampling is critical for cost-effective, defensible audits of large public-sector or enterprise sites.