The Newcastle–Ottawa Scale (NOS) is a tool for assessing the quality of observational studies: cohort and case–control studies. Its star-based assessment covers three areas: selection, comparability, and outcome or exposure.
Observational studies: cohort and case–control studies.
A study earns up to nine stars (at most one per most items, up to two for comparability). More stars indicate higher methodological quality; the good/fair/poor thresholds are set by the review team.
Used in reviews of observational studies to assess the methodological quality of included studies.
The platform applies NOS to full-text project articles and shows a supporting excerpt beneath each judgement.
