How to choose samples that represent the audited service.

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Why sampling matters

Auditing every page of a non-trivial service is rarely possible. The goal of sampling is to choose a set small enough to audit thoroughly but representative enough that the result generalizes.

Sampling dimensions

Pick samples that vary along these axes:

Page type — homepage, navigation index, content page, search results, form, error state, confirmation, login, account settings, media-heavy page.
Layout pattern — different templates and component compositions.
Authentication state — public vs. logged-in.
Content state — empty state, populated state, error state.
Dynamic behavior — pages with significant JavaScript-driven interaction.
Service Criticality – pages within the critical (essential) logic of your service. (product detail, support, checkout, order tracking, etc.)

A sample set that covers all distinct page types and layouts is more useful than one that picks ten pages of the same type.

Sample size guidance

For a small website/service:

Minimum: one sample per distinct page type.
Common: 10 to 15 samples covering the main flows.

For medium service (under ~50 unique templates):

Minimum: one sample per distinct page type + critical paths pages.
Common: 16 to 25 samples covering the main flows and key edge cases.

For larger services:

Identify product-line clusters, sample within each.
Augment with journey-based sampling. See journey mapping.

Sampling and journeys

Page samples and journey maps can overlap. A journey passes through samples that are evaluated in your audits. This is desirable: standalone evaluation catches per-page failures, journey evaluation catches cross-page failures and overall accessibility coverage.

Documenting sampling decisions

Record the reasoning in the audit's scope notes:

What types are represented.
What is intentionally excluded.
Why a particular flow was prioritized.

This makes the audit defensible when challenged. You can take these notes at the audit level, or at the sample level to justify each sample selection.