When evaluating the quality of the information you are using, it is useful to identify if you are using a Primary, Secondary, or Tertiary source. By doing so, you will be able recognize if the author is reporting on his/her own first hand experiences, or relying on the views of others.
Source Type Examples
A primary source is a first person account by someone who experienced or witnessed an event.
This original document has not been previously published or interpreted by anyone else.
A secondary source is one step removed from the primary original source. The author is reexamining, interpreting and forming conclusions based on the information that is conveyed in the primary source.
A tertiary source is further removed from primary source.
It leads the researcher to a secondary source, rather than to the primary source.
Note: Determining whether a source is primary or secondary can be tricky, as the same source could sometimes be primary or secondary depending on how you use it. ex: Ken Burns' documentary of the Civil War is a secondary source for Civil War researchers, but a primary source for those studying documentary filmmaking.
REMEMBER- you cannot always tell what kind of source it is based on where it appears (book, newspaper, academic journal, etc.) - when in doubt ask your instructor or a librarian.