The terms primary (first hand) and secondary (second hand) refer to the degree to which the author of the material experienced the event being described.
When evaluating primary or secondary sources, determine how the author knows the details being described.
Here are some examples:
When working in science and medical research, primary sources are a little different from what you look for in other fields. You'll want to find original research, where the authors actually did the tests, experiments, or observations themselves. The easiest way to find these types of resources is to filter your results by Publication Type, Methodology, and/or Document Type. Here are some things to look for: