Nursing & Allied Health Professions Library Guide

Different study designs present higher level evidence depending on the type of clinical question to be answered.

Case series

A report on a series of patients with an outcome of interest. No control group is involved.

Case-Control Study

Case-control studies begin with the outcomes and do not follow people over time. Researchers choose people with a particular result (the cases) and interview the groups or check their records to ascertain what different experiences they had. They compare the odds of having an experience with the outcome to the odds of having an experience without the outcome.

Cross-sectional study

The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.

Cohort Study (Prospective Observational Study)

Medical, health, and scientific research is based on unique data collection and structuring.

The Johns Hopkins School of Nursing Levels of Evidence are as follows:

Experimental study, randomized controlled trial (RCT)
Systematic review of RCTs, with or without meta-analysis

Quasi-experimental Study
Systematic review of a combination of RCTs and quasi-experimental, or quasi-experimental studies only, with or without meta-analysis.

Non-experimental study
Systematic review of a combination of RCTs, quasi-experimental and non-experimental, or non-experimental studies only, with or without meta-analysis.
Qualitative study or systematic review, with or without meta-analysis

Opinion of respected authorities and/or nationally recognized expert committees/consensus panels based on scientific evidence.
Includes:

• Clinical practice guidelines

• Consensus panels

Based on experiential and non-research evidence.
Includes:

• Literature reviews
• Quality improvement, program or financial evaluation
• Case reports
• Opinion of nationally recognized expert(s) based on experiential evidence

For more information:

Johns Hopkins University Nursing Evidence-Based Practice - Evidence Levels & Quality Guide. (PDF)

Dang, D., & Dearholt, S.L. et al. (2022). Johns Hopkins nursing evidence-based practice : Model & guidelines (4th ed). Sigma Theta Tau International. (Print book in Library.)

There are several ways to determine if an article qualifies as quantitative or qualitative. First, read the abstract. Often there is an explicit mention of methodology that is one or the other, or both. Next, think about the kinds of research methods that are quantitative or qualitative from the rubric of characteristics below. And finally, remember that most qualitative research results in some kind of measurable (or quantitative) data. Because an evidence-based nursing practice relies on objective evidence, measurable data is the standard—even subjective data gathered from qualitative methods will be collated or measured.

If your assignment requires that you find quantitative or qualitative support for your research, build your search using terms that indicate one or the other. For example:       

midwif* AND postpartum qualitative (results will include the word qualitative somewhere)

midwif* AND postpartum interviews (results tend toward qualitative research)

midwif* AND postpartum quantitative (results will include the word quantitative somewhere)

midwif* AND postpartum statistics (results tend toward quantitative research)

Characteristics of quantitative and qualitative research include:

This video demonstrates how to determine if an article is a quantitative study or not.

Is there an author of the document? Can you determine their credentials? If you cannot determine the author of the site, then think twice about using it as a resource.

Is the site sponsored by a group or organization? If it is, does the group advocate a certain philosophy? Try to find and read "About Us" or similar information.

Is there any bias evident in the site? Is the site trying to sell you a product? Ask why the page was put on the web?

Is there a date on the website? Is it sufficiently up-to-date? If there is no date, think twice about using it. Undated factual or statistical information should never be used.

How credible and authentic are the links to other resources? Are the links evaluated or annotated in any way?

Remember!

Evaluating information and successful nursing practice is based on:

"Maintaining a healthy skepticism about the quality and validity of all information." (AAMC)
"Making decisions based on evidence, when such is available, rather than opinion." (AAMC)

• Evaluating Internet Health Information: A Tutorial from the National Library of Medicine
• Consider the HON code

Many scholarly research articles include statistical analysis of numerical data gathered during a study or experiment. To understand these results, check out these explanations.