UPDATED: November 17, 2025. Original Post: July 20, 2020
Integrating the best available health evidence into decision-making processes is an important part of evidence-based practice. However, before applying clinical research findings to patient care, health care providers must determine whether the research findings are valid.
It is important to remember that published studies are not necessarily trustworthy. Healthcare research must be evaluated before being used to guide clinical decisions. Critical appraisal provides a framework for this evaluation.
What is critical appraisal?
Critical appraisal is “the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context.” (CASP)
To critically appraise clinical research is to look at its methodological quality, trustworthiness, and applicability to a patient’s specific situation. Critical appraisal helps us ask two essential questions about a particular research study (Sala Serra & Domingo Torrell, 2022):
- Are the results believable and free of bias or errors? (internal validity)
- Do the results apply to populations other than the sample participants, specifically to my patient’s situation? (external validity)
When should critical appraisal be conducted?
Research should always be critically appraised, no matter its intended use. Such uses may include:
- Patient care in a clinical setting
- Organizational policies or guidelines
- Care directives
- Educational projects
For example, if a recently published study in your discipline suggests a therapy is effective and safe for patients, critically appraising the study ensures the findings are valid and unbiased, and the therapy is appropriate for the specific needs of your patient.
Beyond clinical scenarios, critical appraisal is also a key part of evidence synthesis. As part of the systematic review process, for example, articles included in the review are critically appraised for validity. This ensures that the integrity of the overall review is not impacted by the quality of the individual studies included.
Using critical appraisal checklists
Any type of clinical study can be critically appraised, and each study type has its own checklist. Critical appraisal checklists provide a step-by-step guide through the appraisal process. There are many critical appraisal tools available from organizations that are experts in evidence-based research evaluation, including:
- JBI (formerly Joanna Briggs Institute): Critical Appraisal Tools
- Centre for Evidence-Based Medicine (CEBM): Critical Appraisal Tools
- Critical Appraisal Skills Programme (CASP): Critical Appraisal Checklists
- Scottish Intercollegiate Guidelines Network (SIGN): Critical Appraisal Notes and Checklists
- Critically Appraising for Antiracism Tool (Naicker, R. 2023)
For example, CASP’s Randomised Controlled Trial Checklist includes questions about study methodology such as:
- Was the assignment of participants to interventions randomised?
- Were the investigators ‘blind’ to the intervention they were giving to participants?
- Do the benefits of the experimental intervention outweigh the harms and costs?
- Would the experimental intervention provide greater value to the people in your care than any of the existing interventions?
Critical appraisal for antiracism is rarely addressed in standard tools. To avoid overlooking underrepresented patient populations, consider supplementing your chosen tool with Naicker’s Critically Appraising for Antiracism Tool.
Critical appraisal can be conducted without the use of a formal checklist, but using an established set of appraisal criteria may be helpful if you want to ensure that you are consistent in how you appraise clinical research.
For more info on critical appraisal in your daily work or a larger project, email AskLibrary@nshealth.ca or book a one-on-one consultation with a librarian.
Additional Support
In-depth Resources in Library Services' Searching subject guide.
References
1. CASP - Critical Appraisal Skills Programme. (2025, October 15). What is critical appraisal?. https://casp-uk.net/what-is-critical-appraisal/
2. Naicker, R. (2022). Critically appraising for antiracism. Education for Information, 38(4), 291–308. https://doi.org/10.3233/EFI-220052
3. Sala Serra, M., & Domingo Torrell, L. (2022). Validity of a study: Internal and external validity. Cirugia espanola, 100(10), 649–651. https://doi.org/10.1016/j.cireng.2021.12.007
Selena MacDonald
Librarian Educator
Nova Scotia Hospital, Central Zone
IPPL Clinical Practice and Policy digest posts summarize updates over the past month about:
Original posts on the above topics can be accessed by Nova Scotia Health employees through The Compass > Clinical Resources News.
Clinical Practice Support (CPS) Subject Guides & Policies – Updates
The following CPS subject guides have been updated with new content in the past month:
In consultation with Clinical Nurse Educators (CNEs) in relevant care areas, and with the approval of Critical Care leadership, CL-SP-005 Intra-abdominal Pressure Monitoring has been archived by the Nova Scotia Health Policy Office. CL-SP-005 Intra-abdominal Pressure Monitoring is replaced by the two Dynamic Health skills below, and their corresponding Workplace Notes:
Dynamic Health Updates
Dynamic Health Customizations (Reviews and Custom Skills) Maintenance Schedule
It’s hard to believe, but it has been three years since we published a series of Workplace Notes as a result of our first Dynamic Health skills review!
IPPL Clinical Practice and Policy is committed to revisiting Workplace Notes and Custom Skills every three years, or as current evidence and practice evolves, to keep our collection current.
If you provided a skill review or contributed to the creation of a Custom Workplace Skill in 2023, watch your inbox! Starting November 18, we will be emailing you to update your review or custom skill. If you have moved on or changed roles, please fill out the form link provided in the email and add a colleague who would be best to either take on the skill or point us in the direction of a new reviewer. Please have your responses submitted by January 18, 2026. Thank you for your continued support!
Salem Sump Tubes - Proper Use of Anti-Reflux Valve (ARV)
Cardinal Health has issued product guidance on safe use of the Anti-Reflux Valve (ARV) for Salem Sump tubes.
Review the full update for guidance on The Compass > Clinical Resources News.
Get in Touch!
Connect with Clinical Policy and Practice about this content update and opportunities to collaborate by emailing AskIPPL@nshealth.ca.
Find guidance about using Dynamic Health, setting up a personal account, exporting CE (Continuing Education) Credits, and more in the Dynamic Health Support guide.
IPPL Clinical Practice and Policy
AskIPPL@nshealth.ca