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Dental Hygiene Guide

Qualitative Vs. Quantitative Research Methods 

Appraising scientific evidence: qualitative versus quantitative research

Medical knowledge is derived from a combination of qualitative and quantitative research. Qualitative research refers to the use of non-numerical observations to answer "Why?" questions, while quantitative methods use data that can be counted or converted into numerical form to address "How?" questions. As summarized in Table 5.2, each approach serves a different purpose, so most researchers view the two as complementary and accept a "mixed methods" approach.

Table 5.2: Comparison of qualitative and quantitative research methods

Qualitative research

Quantitative research

Generates hypotheses

Tests hypotheses

Is generally inductive (works from the particular instance to the general conclusion)

Is generally deductive (works from the general theory to the particular explanation)

Focuses on studying the range of ideas; sampling approach provides representative coverage of ideas or concepts

Focuses on studying the range of people; sampling provides representative coverage of people in the population

Answers "why?" and "what does it mean?" questions

Answers "what?", "how much?" and "how many?" questions

Captures rich, contextual, and detailed information from a small number of participants

Provides numeric estimates of frequency, severity, and associations from a large number of participants

Example of a study question: What is the experience of being treated for breast cancer?

Example of a study question: Does treatment for breast cancer reduce mortality and improve quality of life?



”Appraising Scientific Evidence:  qualitative versus quantitative research.” AFMC Primer on Population Health, The Association of Faculties of Medicine of Canada Public Health Educators’ Network, (Accessed September 17, 2015). License: Creative Commons BY-NC-SA

EBM Page Walkthrough

This video will walk you through how to use this page.

What is Evidence-Based Practice?

One of the most common definitions of evidence based practice comes from Dr. David Sackett. He describes EBP as:

"...the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research."

The following graphic breaks down the three components that make up EBP:

Venn Diagram: EBM is in the middle. Best Evidence Available, Clinical Expertise, and Patient Preferences make up the 3 circles in the venn diagram.

Adapted from Duke University Medical Center Library (2015). Introduction to Evidence-Based Practice.

Steps in EBP

While there are differing takes and opinions on the names and number of steps in EBP, they all have the same key concepts:

  1. Ask a clinical question
  2. Search the published literature
  3. Appraise the articles
  4. Integrate the findings into your practice
  5. Evaluate the results
  6. Disseminate (share) your findings

Why Use EBP?

In 2001, the Institute of Medicine (IOM) found that there was an unacceptable gap between what practitioners know and what we they do in the care of patients (IOM, 2001).

Evidence-based practice attempts to bridge this gap by incorporating a review of the current published research, along with the practitioner's own expertise and the patient's preferences. The goal is to help practitioners make informed and personalized treatment-based decisions and deliver the highest quality health care to their patients.

Different Layers of Evidence

When looking for evidenced based medicine, you should recognize that not all published research is identical. Research questions and limitations will guide how a study is designed. The type of study design and its results can produce varying levels of evidence. In other words, you can be more confident about the results in some published studies than others.

The evidence-based pyramid can help navigate the different studies and different levels of evidence. You can find more in depth tutorials and more  at Students 4 Best Evidence Library from the Cochrane Collaboration.

 Evidence Based Pyramid

Try a search in Trip Medical Database to see how search results are filtered by different study design.

How to Find EBP

  • In GALILEO, check peer-review.

  • In Google, try "Clinical Practice Guidelines" or another study design, and pay attention to organizations that practice or regulate health care (CDC, AHA, etc.)

  • Trip Medical Database is a good way to way to view the different types of evidence available. 


This page was adapted with permission from:
Dise, J. (n.d.) Nursing: Evidence based practice.

HLWIKI Canada. (n.d.). Evidence based pyramid. Reposted on

Institute of Medicine. (2001). Crossing the quality chasm: A new health system for the 21st century. Committee on Quality of Health Care in America, Institute of Medicine. National Academies Press.

Sackett, D. L., Rosenberg, W. M. C., Gray, J. A. M., Haynes, R. B., & Richardson, W. S. (1996). Evidence based medicine: What it is and what it isn’t. BMJ, 312(7023), 71–72.

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