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Doctor of Nursing Practice (DNP) Guide

Clinical Study Designs

EBP Clinical Study Designs

Evidence Pyramid

Source: “EBM Pyramid.” Digital Image. Eli M. Oboler Library, 27 May 2016.

Filtered Information      
(secondary literature)

Meta Analysis

An analysis of a body of quantitative research literature focusing on statistical results to evaluate therapeutic effectiveness.

Systematic Reviews

An analysis of a body of primary literature to appraise and synthesize the empirical evidence while minimizing bias. Findings address effects of interventions for prevention, treatment, and rehabilitation.

Critically Appraised Topics (Syntheses of a group of articles or a synthesis of an single article)

A brief assessment of a body of literature (or a single study) to identify what is known and not known about an intervention or issue in order to synthesize the best evidence.

Unfiltered Information      (primary literature)

Randomized Controlled Trials

A work that reports on a clinical trial that involves at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.    PubMed MeSH

Cohort Studies

Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.   PubMed MeSH

Case Control Studies (Case Series / Reports)

Comparisons that start with the identification of persons with the disease or outcome of interest and a control (comparison, referent) group without the disease or outcome of interest. The relationship of an attribute is examined by comparing both groups with regard to the frequency or levels of outcome over time.   PubMed MeSH

Background Information / Expert Opinion

Background information is NOT evidential. Expert Opinion is weak evidence.

Additional Information About Clinical Study Designs

Study Design Decision Tree

           CEBM Centre for Evidence Based Medicine: Overview of the Design Tree