Through a number of criteria including:
Who is the person who created this source? Who publishes this material, or makes it available (Famous Author, occupation, years of experience…)
Are the facts presented in the material correct? How do you know? Can they verified using an outside source?
When was the material published?
Based on the continuous updating of content, including copyright and date last updated
Based on clear vision, not of bias to particular ideas
Based on the coverage of the subject matter in all its aspects, and satisfy the needs of users
Is the information well-organized: can you identify the main points?
Are there errors in spelling, grammar, or punctuation?
Do graphical elements such as tables, charts, illustrations help to make the author's point?
For what this source created? To inform or to persuade? To explain or to sell? to document or to entertain?