Skip to Main Content

Epidemiology HSC4500

A research guide to find epidemiology resources from the EFSC Libraries.

What's the difference? Quantiative Research vs. Qualitative Research

Research studies can fall into two categories, quantitative and qualitative. This chart highlights the differences between each type.

Quantitative Research

Qualitative Research

Observes effects of a problem

Problem studied can be accurately measured

Tests theory
Studies cause and effect
Includes statistical analysis

Can be experimental or non-experimental

Also known as empirical research

Describes a problem and gives it meaning
Problem studied is impossible to accurately or precisely measure
Develops theory
Studies meaning and discovery
Includes narrative analysis

Video: Empirical Studies: Qualitative vs. Quantitative

This video from USU Libraries walks you through the differences between quantitative and qualitative research methods. (5:51 minutes) Creative Commons Attribution license (reuse allowed)

Evidence Pyramid

Consider the type of research article retrieved. The higher on the evidence pyramid, the more credible the article.

Levels of Evidence Pyramid

From University of Illinois Chicago. Library of the Health Sciences. Evidence Based Medicine. Used under a CC BY-NC license.

Levels of Evidence Definitions

The following definitions comes from the BMJ Clinical Evidence Glossary of EBM Terms.

Systematic Review: A review in which...appropriate methods have been used to identify, appraise, and summarise studies addressing a defined question. It can, but need not, involve meta-analysis. A meta-analysis is a statistical technique that summarises the results of several studies in a single weighted estimate, in which more weight is given to results of studies with more events and sometimes to studies of higher quality.

Randomized Controlled Trials: A trial in which participants are randomly assigned to two or more groups: at least one (the experimental group) receiving an intervention that is being tested and another (the comparison or control group) receiving an alternative treatment or placebo. This design allows assessment of the relative effects of interventions.

Cohort Studies: A non-experimental study design that follows a group of people (a cohort), and then looks at how events differ among people within the group.  Prospective cohort studies (which track participants forward in time) are more reliable than retrospective cohort studies (which track participants backwards in time).

Case-Control Studies: A study design that examines a group of people who have experienced an event (usually an adverse event) and a group of people who have not experienced the same event, and looks at how exposure to suspect (usually noxious) agents differed between the two groups. This type of study design is most useful for trying to ascertain the cause of rare events, such as rare cancers.

Case Series: Analysis of series of people with the disease (there is no comparison group in case series).


BMJ Publishing Group. (2012, September 20). A glossary of EBM terms. In EBM Toolbox. Retrieved from