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NURS 7304 - State of the Science: Assessing Evidence

Heirarchy of Evidence

  Level Types of Evidence

Research

Evidence

 I

•    Experimental study, randomized controlled trial (RCT)
•    Explanatory mixed methods design that includes only a Level I quaNtitative study
•    Systematic review of RCTs, with or without meta-analysis
II

•    Quasi-experimental study
•    Explanatory mixed methods design that includes only a Level II quaNtitative study
•    Systematic review of a combination of RCTs and quasi-experimental studies, or quasi-experimental studies only, with or without meta-analysis
III

•    Nonexperimental study
•    Systematic review of a combination of RCTs, quasi-experimental and nonexperimental studies, or nonexperimental studies only, with or without meta-analysis.
•    Exploratory, convergent, or multiphasic mixed methods studies
•    Explanatory mixed methods design that includes only a Level III quaNtitative study
•    QuaLitative study
•    Systematic review of quaLitative studies with or without meta-synthesis

Nonresearch

Evidence

 IV

Opinion of respected authorities and/or nationally recognized expert committees or consensus panels based
on scientific evidence. Includes:
•    Clinical practice guidelines
•    Consensus panels/position statements
V

Based on experiential and non-research evidence. Includes:
•    Scoping reviews
•    Integrative reviews
•    Literature reviews
•    Quality improvement, program or financial evaluation
•    Case reports
•    Opinion of nationally recognized expert(s) based on experiential evidence

 © 2022 Johns Hopkins Health System/Johns Hopkins School of Nursing.

Article Appraisal

QuaNtitative

Collection, analysis, and reporting of numerical data
Numerical data (how many, how much, or how often) are used to formulate facts, uncover patterns, and generalize to a larger population; provides observed effects of a program, problem, or condition. Common methods are polls, surveys, observations, and reviews of records or documents. Data are analyzed using statistical tests.

QuaLitative

Collection, analysis, and reporting of narrative data
Rich narrative data to gain a deep understanding of phenomena, meanings, perceptions, concepts, and experiences from those experiencing it. Sample sizes are relatively small and determined by the point of redundancy when no new information is gleaned, and key themes are reiterated (data saturation). Data are analyzed using thematic analysis. Often a starting point for studies when little research exists; may use results to design empirical studies. Common methods are focus groups, individual interviews (unstructured or semi-structured), and participation/observations.

Mixed methods

Results reported both numerically and narratively
A study design (a single study or series of studies) that uses rigorous procedures in collecting and analyzing both quaNtitative and quaLitative data. Note: QuaNtitative survey designs with open-ended questions do not meet criteria for mixed methods research because those questions are not approached using strict quaLitative methods. Mixed methods studies provide a better understanding of research problems than using either a quaNtitative or quaLitative approach alone.

 © 2022 Johns Hopkins Health System/Johns Hopkins School of Nursing.