Testability

In the context of accessibility standards, testability refers to the degree to which a guideline or success criterion can be evaluated with consistent, reproducible results — either through automated tools (machine testable) or through human inspection where at least 80% of knowledgeable evaluators would agree on the outcome (reliably human testable). Testability was a core design goal of WCAG 2.0, distinguishing it from WCAG 1.0 whose checkpoints often relied on subjective interpretation. A testable criterion is written as a statement that can be determined true or false when specific web content is tested against it, enabling more consistent compliance assessments across different evaluators and tools.