SPCH U301 - Theories and Principles of Human Communication - Dr. Webber: Author & Authority

Technically, "authority" is defined as a person or group's legitimate power over others.  It is the power to influence the opinions of others, esp. because of one's recognized knowledge or scholarship, authoritative opinion, or acknowledged expertise. ^[1]  Regarding research, "authority" relates to whether or not the author(s) has established their expertise.  This expertise may come in many forms, from special skills (training, learned abilities, longevity at a position, etc.); to knowledge derived from formal education and current/continual research. 

You can establish the authority of your sources by researching the author(s).

An expert is:

• a person who has a comprehensive and authoritative knowledge of or skill in a particular area.
• A person regarded or consulted as an authority because of special skill, training, or knowledge; a specialist.

1.  Bealey, Frank (1999). The Blackwell Dictionary of Political Science: A User's Guide to Its Terms. pp. 22–23. ISBN 0-631-20694-9.