What factor primarily determines the credibility of a source?

The credibility of a source is primarily determined by the qualifications and reputation of the author. A well-qualified author typically has relevant education, experience, or expertise in the subject matter, which lends authority to their work. An author’s reputation can also influence credibility; if they are recognized and respected within their field, their findings or viewpoints are more likely to be trusted by readers.

While the length of the publication, the popularity of the topic, and the type of medium used for distribution can influence a reader's perception of a source, they do not inherently reflect the accuracy or reliability of the information presented. For example, a shorter, well-researched paper by a respected expert may be far more credible than a lengthy article by an unknown writer. Similarly, a topic’s popularity does not guarantee the quality or truthfulness of the content, and the medium—whether it be a book, a website, or a journal—does not ensure credible information unless the author behind it is qualified. Overall, the author's qualifications and reputation serve as the foundation for assessing reliability in sources.