In the context of clinical trials, which source is considered a secondary source of evidence?

A literature review article is considered a secondary source of evidence because it does not present original research findings but rather synthesizes and analyzes existing studies on a particular topic. In literature reviews, authors compile data from multiple primary research studies to provide an overview of the current state of knowledge, evaluate trends, and identify gaps in the research. This type of article is valuable because it helps readers understand how different studies relate to one another and what conclusions can be drawn from the collective body of research.

In contrast, a clinical trial report would be a primary source, as it presents original researcher's findings directly from their study. Research findings published in nursing journals would also be primary sources when they report on original studies. Patient feedback research can range between primary and secondary, depending on whether it reports new survey data or compiles patient opinions from various sources. Therefore, the literature review is distinguished by its role in aggregating existing research rather than introducing new findings, solidifying its status as a secondary source of evidence.