In evidence-based practice, there are a variety of methodologies that research can follow in order to reach conclusions that may impact future practice. To learn more about the various study methods and where to search for them, click through the tabs below.
Randomized controlled trials are a subset of clinical trials that follows a randomized and controlled methodology. Participants in an RCT are randomly selected and assigned to either the treatment group or the control group.
With large sample sizes, this method avoids bias and confounding variables as patients are randomly distributed in both experimental conditions - meaning any observed changes in treatment outcomes can be attributed to the treatment's effectiveness.
A cohort study occurs when a group of participants with some shared characteristic (demographics, diagnosis, etc.) are studied over time to observe how frequently certain health outcomes are reached within the cohort.
Most often, cohort studies entail the comparison of two groups, one exposed to a particular circumstance or risk factor and an unexposed control group, to determine if the health outcomes are connected to the exposure. For example, a study comparing smokers to non-smokers over time and observing how many individuals end up with chronic obstructive pulmonary disease (COPD) is a cohort study.
Case-Control studies look to retrospectively compare individuals with a particular condition (cases) to individuals of similar age, sex, and health indicators (controls) to determine what factors may have contributed to the disease or condition developing.
This differs from a cohort study in that in addition to the cohort of individuals with a shared diagnoses, there is a group of control individuals paired up for each participant to serve as a baseline to compare health outcomes to.
In situations where there are rare disease or potentially a very unique dual diagnosis or comorbidity of diseases, it may not be possible to obtain a large enough sample size to perform an RCT, cohort study, or case-control study. In these situations, a case report is performed.
A case report is an extremely detailed report of an individual patient's symptoms, signs, diagnosis, treatment, and health outcomes. Case reports can be helpful in providing critical details for rare cases, but because they only detail one patient's experience, they are not generalizable to the overall patient population.
Evidence syntheses are comprehensive secondary research sources compiled in order to assess empirical evidence more fully. The most common of these formats include systematic reviews and meta-analyses.
Systematic reviews conduct comprehensive literature searches, attempting to find all existing relevant research, appraise its quality, and then summarize key findings to answer a focused clinical research question
Meta-Analyses involve the conducting of a systematic review, and in addition to the systematic review process, provide statistical analysis of the numerical results involved in the studies that address the focused clinical question
Clinical Practice Guidelines (also referred to as just clinical guidelines) are brief, detailed, clinical recommendations for healthcare professionals detailing how best to diagnose and/or treat specific conditions.
These guidelines are updated frequently to ensure information is reflecting current understandings of practice based on empirical health research. The purpose of clinical practice guidelines is to ensure consistent and high-quality care is being delivered to patients.
Clinical practice guidelines are NOT research articles themselves - they are informed by clinical research, but they are used as a blueprint for clinicians on how to provide evidence-based health care.
Grey literature is defined as any scholarly literature produced outside of traditional academic publishing channels. This can include reports, editorials, conference literature, and more.
You may be able to find grey literature in some databases depending on how the database indexes materials, but to comprehensively search grey literature, you need to look outside of databases.