Evidence-appraisal glossary
Reference standard
The best available method for deciding whether the target condition is truly present, against which a new diagnostic test is compared when estimating its accuracy.
Also called: gold standard, criterion standard.
Every reported sensitivity and specificity is measured relative to some reference standard, such as biopsy, long-term follow-up, or an expert-adjudicated diagnosis. When the reference standard is itself imperfect, the new test can look worse than it is or, if the two share the same errors, misleadingly better. A careful reader should ask what the reference standard was and whether it was applied the same way to everyone.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.