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Research Methods in Nursing

Different study types shown in a Pyramid

                             Image provided courtesy of Chico State Meriam Library.

Case Reports

About Case Reports

Case reports (or studies) are lowest level of evidence in this grouping, but have value because they are also the first line of evidence and are where new issues and ideas emerge. This is why they form the base of our pyramid. A good case report will be clear about the importance of the observation being reported.

Case reports are articles that describe and interpret an individual case. They often describe:

  • Unique cases that cannot be explained by known diseases or syndromes
  • Cases that show an important variation of a disease or condition
  • Cases that show unexpected events that may yield new or useful information
  • Cases in which one patient has two or more unexpected diseases or disorders

If multiple case reports show something similar, the next step might be a case-control study to determine if there is a relationship between the relevant variables.

 More Information from: Himmelfarb Library

Definition of Case Study from the Dictionary of Nursing Theory and Research.

Explanation of Case Study Method of Research from the Encyclopedia of Nursing Research.

Finding Case Reports in ASU Databases

Case Control Studies

About Case Control Studies

Case control studies are observational because no intervention is attempted and no attempt is made to alter the course of the disease. The goal is to retrospectively determine the exposure to the risk factor of interest from each of the two groups of individuals: cases and controls. These studies are designed to estimate odds.

A case control study compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease or outcome (controls), and looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between the risk factor and the disease.

They are also known as "retrospective studies" and "case-referent studies."

 More Information from: Himmelfarb Library

Definition of Case Control Study from the Dictionary of Nursing Theory and Research.

Case Control Studies from the Oxford Textbook of Global Public Health.

Finding Case Control Studies in ASU Databases

Some Suggested Search Terms:

Case-Control Studies or Comparison Studies or Control Groups or Matched-Pair Analysis or Retrospective Studies

Cohort Studies

About Cohort Studies

Cohort design is "a study design where one or more samples (called cohorts) are followed prospectively and subsequent status evaluations with respect to a disease or outcome are conducted to determine which initial participants exposure characteristics (risk factors) are associated with it. As the study is conducted, outcome from participants in each cohort is measured and relationships with specific characteristics determined."

 More Information from: Himmelfarb Library

Definition of Cohort from the Dictionary of Nursing Theory and Research.

Explanation of Cohort Design from the Encyclopedia of Nursing Research.

Cohort Studies from the Oxford Textbook of Global Public Health.

Some Suggested Search Terms:

Cohort Studies or Longitudinal Studies or Follow-up Studies or Prospective Studies or Retrospective Studies

Finding Cohort Studies in ASU Databases

Quasi-Experimental Studies

About Quasi-Experimental Studies

A quasi-experiment is an experiment in which the principal independent variable is manipulated by the researcher, and has some controls, but it lacks random assignment of individual subjects to the treatment conditions.

Definition of Quasi-experiment from the Dictionary of Nursing Theory and Research

Explanation of Quasi-experimental Research from the Encyclopedia of Nursing Research

Some Suggested Search Terms:

before-after study or pre-post intervention study

Finding Quasi-Experimental Studies in ASU Databases

Randomized Controlled Trials

About Randomized Controlled Trials

Randomized Controlled Trials (RCT) are Clinical Trials that randomly assign participants into an experimental group or a control group. As the study is conducted, the only expected difference between the control and experimental groups is the outcome variable being studied.

 More Information from: Himmelfarb Library

Definition of Randomized Controlled Trial from Taber's Cyclopedic Medical Dictionary

Definition of Clinical Trial from the Dictionary of Nursing Theory and Research

Explanation of Clinical Trial from the Encyclopedia of Nursing Research

Finding Randomized Controlled Trials in ASU Databases

Systematic Reviews

About Systematic Reviews

A systematic review is a form of secondary research, guided by a detailed review protocol, that gathers primary studies and information from other sources on a clinical or policy question of interest and analyzes the data from these multiple studies to reach a conclusion. A systematic review involves the identification, selection, appraisal, and synthesis of the best available evidence for clinical decision making. A properly conducted systematic review uses transparent and reproducible strategies to reduce bias and instill rigor. It synthesizes information from both published and unpublished sources.

More Information from Encyclopedia of Nursing Research

Definition of Clinical Systematic Reviews from the Dictionary of Nursing Theory and Research

Explanation of Systematic Reviews from the Encyclopedia of Nursing Research

Finding Systematic Reviews in ASU Databases

Free Web-Based Databases

Meta-Analyses

About Meta-Analyses

A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power. This conclusion is statistically stronger than the analysis of any single study, due to increased numbers of subjects, greater diversity among subjects, or accumulated effects and results.

  More Information from: Himmelfarb Library

Definition of Meta-Analysis from the Dictionary of Nursing Theory and Research

Explanation of Meta-Analysis from the Encyclopedia of Nursing Research

Finding Meta-Analyses in ASU Databases

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