Credibility is determined by perceptions of the medium, source, message, and audience. There are three main components that affect credibility:
1. The medium of delivery can impact credibility based on perceptions of whether it is emerging, old, or new.
2. Perceptions of the source or messenger, such as their likability, trustworthiness, dynamism, and composure can influence credibility.
3. Attributes of the message itself like evidence, structure, accuracy, and comprehensiveness also shape how credible it is perceived to be.
4. How others view the source and message, including their collective and reputed knowledge as well as peer ratings, confer credibility from an audience perspective.