Literacy Bias

In accessibility research methodology, a literacy bias describes the phenomenon where an evaluation metric systematically produces different scores for participants with different reading-literacy levels, independent of the characteristic being measured. For example, comprehension questions and subjective understandability judgements often yield higher scores from higher-literacy readers even when the texts being evaluated are identical, because higher-literacy readers have stronger meta-cognitive awareness of whether they understood something. A literacy bias does not render a metric unusable, but when such a metric is used in a study, researchers should report participant literacy levels so that results can be fairly compared across studies with different reader profiles.