- Systematic discrepancy between a measurement and the true value; may be constant or proportionate and may adversely affect test results.
- Any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that differ systematically from the truth; deviation of results or inferences from the truth, or processes leading to deviation.
[Fr. biais, obliquity, perh. fr. L. bifax, two-faced]