Newcastle-Ottawa Scale — Quality Assessment Guide
The Newcastle-Ottawa Scale (NOS) is the most widely used tool for assessing quality of non-randomised studies in systematic reviews. This guide covers scoring for cohort and case-control studies, with examples and common scoring pitfalls.
Audience
Systematic reviewers, epidemiologists, and evidence synthesis teams.
Use Case
Score non-randomised studies using NOS for quality assessment in systematic reviews.
Guide Depth
4 steps · 5 features
Workflow
- 1Identify whether each study is a cohort or case-control design.
- 2Score each study across selection, comparability, and outcome domains.
- 3Use the NOS star system to classify study quality.
- 4Integrate NOS scores with GRADE assessment for overall evidence certainty.
Outcome Signals
- Consistently assess study quality in systematic reviews
- Reduce inter-reviewer disagreement with clear scoring criteria
- Support GRADE certainty ratings with standardized quality assessment
Execution Checklist
- NOS scoring guide for cohort and case-control studies
- Star allocation examples for each domain
- Common scoring mistakes and how to avoid them
- Integration with GRADE evidence quality framework
- Downloadable NOS scoring templates
Common Questions
Composite Team Feedback
Representative feedback patterns from teams using this kind of medical literature workflow.
Clinician
"Paper review now tells me what the methods and figures actually mean before I rely on a study in practice."
Faster evidence triage for high-stakes reading
Clinical Pharmacist
"We use these workflows to sanity-check new evidence before it changes how we update recommendations."
More confident evidence decisions