Secondary sources often analyze primary sources to argue/ support a thesis statement.
Secondary sources interpret the significance or meaning of an historical event or phenomenon; person; a movement; or a place.
Secondary sources are often created by someone not present when the event took place or removed from the event.
Secondary sources are produced and disseminated in a variety of formats including books, scholarly journal articles, conference proceedings, dissertations, documentaries, and reference works.
Primary Sources Video from JSTOR
Confused about how to distinguish between primary and secondary sources? This short video from JSTOR may help.