Genealogical evidence results from proper analysis of information to determine how relevant and adequate that information is for answering a particular question. Evidence may be either direct (if it directly answers the question) or indirect (if it infers or implies an answer to the question). For example, if one finds information stating "Hannah, d. of Benjamin and Hannah Winslow was b. 2 April 1705", that is direct evidence of the birth date and parentage of Hannah the daughter, but also provides indirect evidence of the probable marriage of her parents.
Source: Elizabeth Shown Mills, Working With Historical Evidence: Genealogical Principals and Standards, NGSQ 87:3 (September 1999).