A secondary source is a scholarly discussion based on primary sources. Typically, a secondary source contains original research.
Why should I use secondary sources?
Secondary sources are useful for in-depth analysis of your topic and for learning about scholarly perspectives on your topic. You can use a secondary source as a conversation partner about a topic or you can take the methodology from a secondary source an apply it to a new research question.
What are some examples of secondary sources?
Secondary sources include articles, blogs, books (often called monographs), lectures, podcasts, and scientific reports. Any kind of scholarly liter can be a secondary source.
Pro tip: Although the distinction between primary sources and secondary sources is useful, it is not absolute. A secondary source may become a primary source depending on the researcher's perspective. Consider a textbook on American history from the 1990's. If a researcher uses the textbook for a scholarly perspective on the civil rights movement, then it is a secondary source. However, if the researcher uses the textbook to as evidence of curriculum in the 1990's, then it is a primary soruce.