Nursing

ORIGINAL STUDIES (primary sources)

Randomized Controlled Trial

Participants are randomly assigned to receive a given exposure (such as a new drug or therapy) and then followed to examine the effects of the exposure on outcomes.

Cohort Study

One or more population groups (called cohorts) are classified according to their level of exposure to a given agent/risk factor and followed over time to determine if this exposure is related to the occurrence of a disease or outcome of interest.

Case–Control Study

Compares individuals with a disease or outcome of interest (cases) with those who do not (controls). Researchers look retrospectively to evaluate how frequently exposure to a risk factor/agent is present in each group to identify the relationship between the risk factor and the disease or outcome of interest.

Cross-Sectional Study

Observes the relationship between a characteristic/risk factor (the exposure) and the prevalence of the disease or outcome of interest in a specific population at a single point in time

Case Series 

A summary of a small group of individuals’ experience with a similar disease or outcome of interest

Case Reports

A summary of one individual’s experience with the disease or outcome of interest

SECONDARY STUDIES (studies of studies)

Meta-analysis 

A type of systematic review in which results from available high-quality studies are statistically combined to compute a net overall effect.

Systematic Review 

A comprehensive summary of high-quality studies examining a given topic.

Practice Guideline 

(also known as Clinical Practice Guideline Evidence-Based Guideline)

 Statements that include recommendations intended to optimize patient care. Guidelines are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options.