Nursing Guide

Library FAQs

Databases for NSC 890

Remember that while some databases, like CINAHL, have limiters which target particular types of research studies, you can always use the type of study as a search term in addition to your topic: randomized controlled trial, qualitative, systematic review, etc.  This will work in any database including CINAHL.

Other Considerations

Librarians will be happy to help coach you in your searches, by suggesting databases, search terms, limiters, etc.  Sometimes we demonstrate searches to model search techniques that you can use in the future.  Our goal is to help you become self-sufficient so that you can find evidence-based content throughout your professional life.

Once we have helped you start some searches, it’s very likely that the resulting articles will differ in quality; as with any search, some will meet your requirements and some will be less useful.  This is the point where you will need to do some digging and exercise your critical thinking skills.  The level of research you are currently performing can be both time-consuming and sometimes frustrating; but it is always worthwhile!

Levels of Evidence from Melnyk & Fineout-Overholt (2015). Evidence-Based practice in nursing & healthcare (3rd ed.).

Hierarchy of Evidence for Intervention Studies

Type of evidence Level of evidence Description
Systematic review or meta-analysis I A synthesis of evidence from all relevant randomized, controlled trials.
Randomized, controlled trial II An experiment in which subjects are randomized to a treatment group or control group.
Controlled trial without randomization III An experiment in which subjects are nonrandomly assigned to a treatment group or control group.
Case-control or cohort study IV

Case-control study: a comparison of subjects with a condition (case) with those who don’t have the condition (control) to determine characteristics that might predict the condition.

Cohort study: an observation of a group(s) (cohort[s]) to determine the development of an outcome(s) such as a disease.

Systematic review of qualitative or descriptive studies V A synthesis of evidence from qualitative or descriptive studies to answer a clinical question.
Qualitative or descriptive study VI

Qualitative study: gathers data on human behavior to understand why and how decisions are made.

Descriptive study: provides background information on the what, where, and when of a topic of interest.

Opinion or consensus VII Authoritative opinion of expert committee.


Cochrane Library

When using the Cochrane Library, which is a collection of databases that contain different types of high-quality, independent evidence, you will specifically search two: the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials. I recommend searching them separately.  To do so, access the database at, select Choose Databases, uncheck all that don't apply, click OK and start searching.