In scientific research, primary sources are the original studies where researchers present new data, methods, and findings — for example, a paper reporting the results of an experiment or clinical trial.
Secondary sources, by contrast, don’t present new experiments; instead, they review, analyze, and summarize multiple primary studies on a topic. These are often called review articles or meta-analyses. Both are scholarly, but they serve different purposes: primary articles move knowledge forward one study at a time, while secondary articles give you a broader view of what’s already been discovered and how studies fit together.