Guide to Health Literacy xix the likely credibility of the health information they are conveying. While books often have implied credibility because of the peer-review process involved, self-publishing has challenged this credibility, so qualifications of book authors should also be verified. When it comes to health infor- mation, currency of the source must also be examined. When examining health information/studies presented, pay attention to the exhaustiveness of research methods utilized to offer recommendations or conclusions. Small and nondiverse sample size is often—but not always—an indication of reduced credibility. Studies that confuse correlation with causation is another potential issue to watch for. Information seekers must also pay attention to the sponsors of the research studies. For example, if a study is sponsored by manufacturers of drug Y and the study recommends that drug Y is the best treatment to manage or cure a disease, this may indicate a lack of objectivity on the part of the researchers. The Internet is rapidly becoming one of the main sources of health information. Online forums, news agencies, personal blogs, social media sites, pharmacy sites, and celebrity “doctors” are all offering medical and health information targeted to various types of people in regard to all types of diseases and symptoms. There are professional journalists, citizen journalists, hoaxers, and people paid to write fake health news on various sites that may appear to have a legitimate domain name and may even have authors who claim to have professional credentials, such as an MD. All these sites may offer useful information or information that appears to be useful and relevant however, much of the information may be debat- able and may fall into gray areas that require readers to discern credibility, reliability, and biases. While broad recognition and acceptance of certain media, institu- tions, and people often serve as the most popular determining factors to assess credibility of health information among young people, keep in mind that there are legitimate Internet sites, databases, and books that publish health information and serve as sources of health information for doctors, other health sites, and members of the public. For example, Med- linePlus (https://medlineplus.gov) has trusted sources on over 975 dis- eases and conditions and presents the information in easy-to-understand language. The chart here presents factors to consider when assessing credibility of health information. However, keep in mind that these factors function only as a guide and require continuous updating to keep abreast with the changes in the landscape of health information, information sources, and technologies.