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PSY 3100 - Research Methods

This research guide is for the psychological science research methods course.

Evidence Based Practice (EBP)

Evidence Based Practice (EBP) is an umbrella term for many different aspects of evidence based practice. EBP includes evidence-based medicine, evidence-based nursing, evidence-based physical therapy, evidence-based dentistry, etc.Evidence-Based Practice Triangle

Evidence-based practice (EBP) is the combination of

  • Clinical expertise
    The knowledge acquired through training and professional experiences
  • Evidence
    The best available information gathered from the scientific literature (external evidence) and from data and observations collected on your individual client (internal evidence)
  • Client/patient/caregiver perspectives
    The unique set of personal and cultural circumstances, values, priorities, and expectations identified by your client and their caregivers

When all three components of EBP are considered together, clinicians can make informed, evidence-based decisions and provide high-quality services reflecting the interests, values, needs, and choices of individuals with communication disorders.

AHSA. (n.d.). Evidence Based Practice (EBP). Retrieved from https://www.asha.org/members/ebp/

Levels of Evidence

The level of evidence can be defined by the type of question. Levels of evidence for a "Therapy" question are different from the levels of evidence for an "Etiology" question. 

Level of evidence (LOE)

Description

Level I

Evidence from a systematic review or meta-analysis of all relevant RCTs (randomized controlled trial) or evidence-based clinical practice guidelines based on systematic reviews of RCTs or three or more RCTs of good quality that have similar results.

Level II

Evidence obtained from at least one well-designed RCT (e.g. large multi-site RCT).

Level III

Evidence obtained from well-designed controlled trials without randomization (i.e. quasi-experimental).

Level IV

Evidence from well-designed case-control or cohort studies.

Level V

Evidence from systematic reviews of descriptive and qualitative studies (meta-synthesis).

Level VI

Evidence from a single descriptive or qualitative study.

Level VII

Evidence from the opinion of authorities and/or reports of expert committees.

 

The table above is based on the following: Ackley, B. J., Swan, B. A., Ladwig, G., & Tucker, S. (2008). Evidence-based nursing care guidelines: Medical-surgical interventions. (p. 7)St. Louis, MO: Mosby Elsevier
.

Research Study Designs

The level of evidence can be defined by the type of question. Levels of evidence for a "Therapy" question are different from the levels of evidence for an "Etiology" question. 

Clinical Question

Suggested Research Design(s)

All Clinical Questions

Systematic review, meta-analysis

Therapy

Randomized controlled trial (RCT), meta-analysis 
Also: cohort study, case-control study, case series

Etiology

Randomized controlled trial (RCT), meta-analysis, cohort study 
Also: case-control study, case series

Diagnosis

Randomized controlled trial (RCT) 
Also: cohort study

Prevention

Randomized controlled trial (RCT), meta-analysis 
Also: prospective study, cohort study, case-control study, case series

Prognosis

Cohort study
Also: case-control study, case series

Meaning

Qualitative study

Quality Improvement

Randomized controlled trial (RCT) 
Also: qualitative study 

Cost

Economic evaluation

 

The table above is based on the following: Ackley, B. J., Swan, B. A., Ladwig, G., & Tucker, S. (2008). Evidence-based nursing care guidelines: Medical-surgical interventions. (p. 7)St. Louis, MO: Mosby Elsevier.

Levels of Evidence Pyramid

The levels of evidence pyramid is a  way to visualize both the quality of evidence and the amount of evidence available. For example, systematic reviews are at the top of the pyramid, meaning they are both the highest level of evidence and the least common. As you go down the pyramid, the amount of evidence will increase as the quality of the evidence decreases.

Levels of Evidence Pyramid

Text alternative for Levels of Evidence Pyramid diagram

EBM Pyramid and EBM Page Generator, copyright 2006 Trustees of Dartmouth College and Yale University. All Rights Reserved. Produced by Jan Glover, David Izzo, Karen Odato and Lei Wang.

Finding Evidence Based Resources