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Ask A Librarian: Evaluating Health Information on the World Wide Web

Q: I keep reading about substance abuse and health on the web,  and sometimes what I read conflicts with what I see in magazines and government advisories.  How do I know who and what to believe?

A: It is easy to feel overwhelmed by the proliferation of choices of information including print media, television, and the World Wide Web. What sources on the web are credible?  What authorities should one consult?  Health information literacy is a subset of “information literacy,” which can be defined as the set of skills needed to find, retrieve, analyze, and use information.

Q: I keep reading about substance abuse and health on the web,  and sometimes what I read conflicts with what I see in magazines and government advisories.  How do I know who and what to believe?

A: It is easy to feel overwhelmed by the proliferation of choices of information including print media, television, and the World Wide Web. What sources on the web are credible?  What authorities should one consult?  Health information literacy is a subset of “information literacy,” which can be defined as the set of skills needed to find, retrieve, analyze, and use information.

To help you to decide if a web site is a source you can trust, start by asking yourself questions about it:

1. Who runs the Web site?

Any good health web site should make it easy to learn who is responsible for the site and its information.  The responsible organization should be noted on every major page along with a link to the site's home (main) page.  Information about who owns or runs the website can often be found in an "About Us" or "About This Web Site" section, and there's usually a link to that section on the site's home page.

2. What is the purpose of the Web site?

Is the purpose of the site to inform? Is it to sell a product? Is it to raise money? If you can tell who runs and pays for the site, this will help you evaluate its purpose and its point of view.

3. What is the original source of the information on the Web site?

Always pay close attention to where the information on the site comes from. Many health and medical web sites post information collected from other Web sites or print sources. If the person or organization in charge of the site did not write the material, the original source should be clearly identified. Be careful with sites that do not provide documentation of their data or assertions. 

Good sources of health information include:

• Sites that end in “.gov,” sponsored by the federal government, like the U.S. Department of Health and Human Services (www.hhs.gov), the FDA (www.fda.gov), the National Institutes of Health (www.nih.gov), the Centers for Disease Control and Prevention (www.cdc.gov), and the National Library of Medicine (www.nlm.nih.gov)
• “.edu” sites, which are run by universities or medical schools, such as the Indiana University School of Medicine, Harvard University School of Public Health, Johns Hopkins University School of Medicine, and other health care facility sites, such as the Mayo Clinic and the Cleveland Clinic
• “.org” sites maintained by not-for-profit groups whose focus is research and teaching the public about specific diseases or conditions, such as the American Diabetes Association, the American Cancer Society, and the American Heart Association
• Medical and scientific journals, such as The New England Journal of Medicine and the Journal of the American Medical Association (although these aren't written for the general public) and databases that aggregate journals and may even include full text articles, such as the National Library of Medicine website,  PubMed http://www.ncbi.nlm.nih.gov/sites/entrez/.
• Sites whose addresses end in “.com” are usually commercial sites and are often selling products.

4. How is the information on the Web site documented?

In addition to identifying the original source of the material, the site should identify the evidence on which the material is based. Medical facts and figures should have references (such as citations of articles in medical journals). Also, opinions or advice should be clearly set apart from information that is "evidence-based" (that is, based on research results).

5. How is information reviewed before it is posted on the Web site?

Health-related Web sites should give information about the medical credentials of the people who prepare or review the material on the Web site.

6. How current is the information on the Web site?

Web sites should be reviewed and updated on a regular basis. It is particularly important that medical information be current, and that the most recent update or review date be clearly posted. These dates are usually found at the bottom of the page. Even if the information has not changed, it is helpful to know that the site owners have reviewed it recently to ensure that the information is still valid. Click on a few links on the site. If there are a lot of broken links, the site may not be kept up-to-date.

7. How does the Web site choose links to other sites?

Reliable Web sites usually have a policy about how they establish links to other sites. Some health or medical Web sites take a conservative approach and do not link to any other sites; some link to any site that asks or pays for a link; others link only to sites that have met certain criteria. Look for the web site's linking policy, often found in a section titled "About This Web Site."

8. What information about its visitors does the Web site collect, and why?

Web sites routinely track the path visitors take through their sites to determine what pages are being used. However, many health-related web sites ask the visitor to "subscribe" or "become a member." In some cases, this may be done so they can collect a fee or select relevant information for the visitor. In all cases, the subscription or membership will allow the Web site owners to collect personal information about their visitors.

Many commercial sites sell "aggregate" data about their visitors to other companies. In some cases, they may collect and reuse information that is personally identifiable, such as a visitor's ZIP code, gender, and birth date.

Any web site asking users for personal information should explain exactly what the site will and will not do with the information. Be sure to read and understand any privacy policy or similar language on the site, and don't sign up for anything you don't fully understand.

9. How does the Web site manage interactions with visitors?

There should always be a way for visitors to contact the web site owners with problems, feedback, and questions. If the site hosts a chat room or other online discussion areas, it should tell its visitors about the terms of using the service. Is the service moderated? If so, by whom, and why? It is always a good idea to spend time reading the discussion without joining in, to feel comfortable with the environment, before becoming a participant.