A Guide to Global Health and Epidemiology Research

The assumption is that a health practitioner knows the right thing to do. This is called ‘clinical judgment’. The assumption is, you are able to assimilate all you have learned from your education, training, research, personal experiences, and conversations, so be prepared to ask ‘What is the evidence to support my question’? See below for Levels of Evidence.

Rating System for the Hierarchy of Evidence/Levels of Evidence

• Level I — Evidence for a systematic review or meta-analysis of all relevant RCTs or evidence-based clinical practice guidelines based on systematic reviews of RCTs.
• Level II — Evidence obtained from one well-designed controlled trials without Randomization
• Level III — Evidence obtained from one well-designed controlled trials without Randomization
• Level IV — Evidence from well-designed case-control and cohort studies
• Level V — Evidence from systematic reviews of descriptive or qualitative study
• Level VI — Evidence from single descriptive or qualities study
• Level VII — Evidence from the opinion of authorities and/or reports of expert committees

Melnyk, B. M., & Fineout-Overholt, E. (2014). Evidence-based practice in nursing & healthcare: A guide to best practice. Lippincott Williams & Wilkins.

Library Health Article Resources: University libraries have electronic databases of medical literature.  Librarian Tip: Library Health Article Resources are an excellent place to start. See them under Searching Resources. 

Government Web Sites: Government-funded web sites tend to have explicit quality assurance processes and are likely to be reliable.  

Health Organizations and Association Web Sites: These can provide information and resources about health conditions.

Consumer Health Bodies and Self-Help Groups: Online sources - not all information is evidence-based or reliable quality.

Media Sources:  Media content about health discoveries should be tested by looking into the study design and consider whether effects are reported in actual numbers. Health News Review: provides audiences some feedback about the accuracy of media reports.

For Profit Companies: such as Pharmaceutical companies (private enterprises) - be skeptical as there may be bias.

SUNY Downstate Medical Research Library of Brooklyn

MEDLINE and the other online medical literature databases try to be as comprehensive as possible in their coverage. As a result, indexed material may have little direct application to present-day medical practice.

The different types of material indexed in MEDLINE are labeled in the pyramid diagram, with the least clinically relevant at the bottom and the most clinically relevant at the top. The four layers above case reports and case series represent actual clinical research; the layers below are least clinically relevant and can be useful as background resources.

The links below provide basic definitions and examples of clinical research designs to help the medical student or new clinician understand how the design of a research study may affect whether or not to accept its findings in caring for a patient.

More detail on each level is available by reading the pages in sequential order or by selecting from the topics below:

NAU Librarians are available and can assist you by chat or email. You can schedule an individual research appointment.  We will reply to emails within 24 hours, Monday through Friday (excluding holidays or other closures).   View all hours.

Recognizing Key Components in a Primary Research Article.