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NUR 412 Evidence-Based Practice

Evidence Based Practice Pyramid

Peterson, M. H., Barnason, S., Donnelly, B., Hill, K., Miley, H., Riggs, L., & Whiteman, K. (2014). Choosing the best evidence to guide clinical practice: application of AACN levels of evidence. Critical Care Nurse, 34(2), 58-68.

Levels of Evidence

When conducting research in nursing, the majority of your sources should come from articles that appear in levels A, B, and C.  These studies are experimental in nature and provide evidence-based recommendations for your research.

Level

A - Meta-analysis or meta-synthesis of multiple controlled studies with results that consistently support a specific action, intervention, or treatment (systematic review of a randomized controlled trial)

B - Evidence from well-designed controlled studies, both randomized and non-randomized, with results that consistently support a specific action, intervention, or treatment.

C - Evidence from qualitative, integrative reviews, or systematic review of qualitative, descriptive, or correlational studies or randomized controlled trials with inconsistent results.

Peterson, M. H., Barnason, S., Donnelly, B., Hill, K., Miley, H., Riggs, L., & Whiteman, K. (2014). Choosing the best evidence to guide clinical practice: application of AACN levels of evidence. Critical Care Nurse, 34(2), 58-68.

Level

D - Evidence from peer-reviewed professional organizational standards, with clinical studies to support recommendations

E - Theory-based evidence from expert opinion or multiple case reports

M - Manufacturer's recommendation only

Peterson, M. H., Barnason, S., Donnelly, B., Hill, K., Miley, H., Riggs, L., & Whiteman, K. (2014). Choosing the best evidence to guide clinical practice: application of AACN levels of evidence. Critical Care Nurse, 34(2), 58-68.

Types of Studies

Research articles are found in two main groups: Experimental and non-experimental.  Your best sources of evidence come from experimental studies.  Focus on these studies first before moving into non-experimental areas. 

Meta-Analysis
  • Level of Evidence - A
  • Definition - A technique for qualitatively integrating the results of multiple similar studies addressing the same research question.
  • Strengths - Statistical summary of articles of the same topic in research; process of using quantitative methods to summarize the results from multiple studies.
  • Limitations - Usually lengthy; combines like research studies
Systematic Review
  • Level of Evidence - A if quantitative study, C if qualitative study
  • Definition - A rigorous synthesis of research findings on a particular research question obtained by using systematic sampling and data collection procedures and a formal protocol
  • Strengths - Review by experts in the field of all the research on a topic, who rigorously appraise the studies and offer the conclusion to support an intervention or not.
  • Limitations - Only as good as the search methods and databases used.
Randomized Controlled Trial
  • Level of Evidence - B
  • Definition - A full experimental test of an intervention, involving random assignment to treatment groups
  • Strengths - True experimental study in which the researchers are often blinded to which patients or participants are receiving an intervention; the strongest design for examining the cause and effect of an intervention; reduces bias
  • Limitations - Time-consuming; May require more sophisticated statistical analysis

Peterson, M. H., Barnason, S., Donnelly, B., Hill, K., Miley, H., Riggs, L., & Whiteman, K. (2014). Choosing the best evidence to guide clinical practice: application of AACN levels of evidence. Critical Care Nurse, 34(2), 58-68.

Non-experimental

Cohort Study
  • Level of Evidence - C
  • Definition - A non-experimental design in which a group of people (a cohort) is followed over time to study outcomes
  • Strengths - Prospective longitudinal study that examines 2 groups of patients or participants (the cohort)
  • Limitations - Observational; No intervention performed; May include attrition
Case-controlled Study
  • Level of Evidence - C
  • Definition - A non-experimental research design involving the comparison of a case and a matched control.
  • Strengths - Longitudinal study that retrospectively compares characteristics of an individual who has a certain type of condition that may not be very common; often used to identify variables that may predict the etiology or the course of a disease
  • Limitations - Retrospective
Integrative Review
  • Level of Evidence - C
  • Definition - Reviews of qualitative studies, often taking the form of meta-syntheses, which are rich sources for evidence-based practice
  • Strengths - Compilation of studies that are reviewed and summarized; may incorporate research and non-research articles
  • Limitations - Not as rigorous as systematic reviews; review limited to the literature
Meta-synthesis
  • Level of Evidence - C
  • Definition - Interpretive translations produced from the integration or comparison of findings from qualitative studies on a specific topic
  • Strengths - Compilation of qualitative studies looking for common themes among similar research studies
  • Limitations - Interpreted by the researcher
Qualitative research
  • Level of Evidence - C
  • Definition - Investigation of phenomena, typically in an in-depth and holistic fashion, through the collection of rich narrative materials by using flexible research design
  • Strengths - Method to develop a greater understanding of a topic using many different methods such as observation or interview
  • Limitations - Some believe it to be less rigorous. 

Peterson, M. H., Barnason, S., Donnelly, B., Hill, K., Miley, H., Riggs, L., & Whiteman, K. (2014). Choosing the best evidence to guide clinical practice: application of AACN levels of evidence. Critical Care Nurse, 34(2), 58-68.