Table 2. Analysis criteria.

Form and design criteria
• Clear structure and organization of content (yes/no)
• Ease of navigation, “user-friendliness” (yes/no)

Content criteria
• Information relevance and coherence: congruence between key word search and output (yes/no)
• Scientific rigor: adequate citations. In non-scientific sites, explicit mention of the fact that the site’s content does not replace the advice of a health professional (yes/no)
• Covers a wide scope on the subject and presents an accurate and comprehensive message (yes/no)
• Message clarity and comprehensibility. Use of understandable language (yes/no)
• Updated information, maintenance of site, mention of last content review date (yes/no)
• Presence of advertising and sponsor links on the site: clarity and transparency of such links, properly distinguished from the rest of the content (yes/no)

Credibility criteria
• Mention of the author/s and their qualifications. Includes author / institution contact details and address (yes/no)
• Scientific Association accreditations (yes/no)
• Accreditation certificate or trust mark (HON, WMA, WIS, PWMC or others) (yes/no)
• Clear statement of bibliographical sources. Reliable references for specialists cited (yes/no)

Site assessment based on rating of established criteria, namely form and design, content and credibility.