NUR152 - EBP Research Guide

Evidence-Based Practice is the integration of best research evidence with clinical expertise and patient values. (Sackett DL, Straus SE, Richardson WS, et al. Evidence-based medicine: how to practice and teach EBM. 2nd ed. Edinburgh: Churchill Livingstone, 2000.) 

Unfiltered resources are primary sources that describe original research.  Randomized controlled trials, cohort studies, case-controlled studies, and case series/reports are considered unfiltered information.  

Filtered resources are secondary sources that summarize and analyze the available evidence.  They evaluate the quality of individual studies and often provide recommendations for practice.  Systematic reviews, critically-appraised topics (e.g., meta-analysis) and critically-appraised individual articles are considered filtered information.

This should be an ongoing process in clinical practice and therefore it may also be illustrated as a circle (see above box).

Note: Credit for the above >

Meta-Analysis
A way of combining data from many different research studies. A meta-analysis is a statistical process that combines the findings from individual studies.  Example:

Systematic Review
A summary of the clinical literature. A systematic review is a critical assessment and evaluation of all research studies that address a particular clinical issue. The researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a set of specific criteria. A systematic review typically includes a description of the findings of the collection of research studies. The systematic review may also include a quantitative pooling of data, called a meta-analysis.  Example:

Randomized Controlled Trial
A controlled clinical trial that randomly (by chance) assigns participants to two or more groups. There are various methods to randomize study participants to their groups.  Example:

Cohort Study (Prospective Observational Study)
A clinical research study in which people who presently have a certain condition or receive a particular treatment are followed over time and compared with another group of people who are not affected by the condition.  Example:

Case-control Study
Case-control studies begin with the outcomes and do not follow people over time. Researchers choose people with a particular result (the cases) and interview the groups or check their records to ascertain what different experiences they had. They compare the odds of having an experience with the outcome to the odds of having an experience without the outcome.  Example:

Cross-sectional study
The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.  Example:

 Case Reports and Series
A report on a series of patients with an outcome of interest. No control group is involved.  Example:

Ideas, Editorials, Opinions
Put forth by experts in the field.  Example:

Animal Research Studies
Studies conducted using animal subjects.  Example:

Test-tube Lab Research
"Test tube" experiments conducted in a controlled laboratory setting.

Adapted from Study Designs. In NICHSR Introduction to Health Services Research: a Self-Study Course and Glossary of EBM Terms.

NOTE: Credit for the above content is given to ***public health: General subject guide: About study designs. GSU Library Research Guides from https://research.library.gsu.edu/ph/studydesigns.

Types of studies we are going to cover fall under one of two categories - primary sources or secondary sources. Primary sources are those that report original research and secondary sources are those that compile and evaluate original studies.

Primary Sources

Randomized Controlled Trials are studies in which subjects are randomly assigned to two or more groups; one group receives a particular treatment while the other receives an alternative treatment (or placebo). Patients and investigators are "blinded", that is, they do not know which patient has received which treatment. This is done in order to reduce bias.

Cohort Studies are cause-and-effect observational studies in which two or more populations are compared, often over time. These studies are not randomized.  

Case Control Studies study a population of patients with a particular condition and compare it with a population that does not have the condition. It looks the exposures that those with the condition might have had that those in the other group did not.

Cross-Sectional Studies look at diseases and other factors at a particular point in time, instead of longitudinally. These are studies are descriptive only, not relational or causal. A particular type of cross-sectional study, called a Prospective, Blind Comparison to a Gold Standard, is a controlled trial that allows a research to compare a new test to the "gold standard" test to determine whether or not the new test will be useful.

Case Studies are usually single patient cases.  

Secondary Sources

Systematic Reviews are studies in which the authors ask a specific clinical question, perform a comprehensive literature search, eliminate poorly done studies, and attempt to make practice recommendations based on the well-done studies.

Meta-Analyses are systematic reviews that combine the results of select studies into a single statistical analysis of the results.

Practice Guidelines are systematically developed statements used to assist practitioners and patients in making healthcare decisions.  

(Credit: https://libguides.salemstate.edu/c.php?g=956797&p=7225309)

Different types of clinical questions have certain kinds of studies that best answer them. The chart below lists the categories of clinical questions and the studies you should look for to answer them.

Source: A Dictionary of Nursing