Prepared by Elisabeth Lindsay.
The word "secondary" indicates being second in rank or value and stands in contrast to "primary," which is considered first in rank or value. The term "secondary source" in reference to a document is no longer used within the genealogy community; rather, the term "secondary information" is used in reference to secondhand information -- information that may be known but not witnessed. Original source and derivative source documents can contain both primary information (firsthand knowledge) and secondary information (secondhand knowledge), and both have a place in genealogy research. Secondary information, however, by its nature has a greater margin of error and should be verified.
Secondary information can be useful in providing genealogical leads, but should not be taken at face value. User-generated family trees and published genealogies are among the most suspect of all genealogical records and constitute a derivative source. In today's Internet environment, incorrect information can be replicated with lightening speed, so it is always important to evaluate your source and the type of information it contains. The more credible family trees and genealogies document their sources, which make it easier for you to examine information and research any conflicts.