Media Effects Research Lab - Research Archive

Doctors vs. laypersons on blogs vs. bulletin boards vs. websites vs. homepages: The effects of online health sources on credibility and behavioral intentions

Student Researcher(s)

Yifeng Hu (Ph.D Candidate)

Faculty Supervisor

Dr. S. Shyam Sundar


Hu, Y., & Sundar, S. S. (2008, May). Doctors vs. Laypersons on Blogs vs. Bulletin Boards vs. Websites vs. Homepages: The Effects of Online Health Sources on Credibility and Behavioral Intentions. Paper presented at the 58th annual convention of the International Communication Association, Montreal, Canada.


Based on a typology of online communication sources, this research examines the influences of original sources (doctors vs. laypersons) and selecting sources (websites vs. bulletin boards vs. blogs vs. homepages) on perceived credibility of—and behavioral intentions toward—health information. A large 2 × 2 × 5 full factorial online experiment revealed that respondents (N = 555) were more likely to take action based on the information sourced from a website than from a blog or a homepage. The effect was mediated by perceived level of gatekeeping and perceived information completeness. A two-way interaction between original and selecting sources was mediated by perceived appropriateness of source placement such that information on a website was perceived as more credible if attributed to a doctor than to a layperson while information on a homepage was perceived as slightly more credible if attributed to a layperson. This interaction differed as a function of message. Practical implications for online health planners, physicians, users and policy makers are discussed.

For more details regarding the study contact

Dr. S. Shyam Sundar by e-mail at or by telephone at (814) 865-2173

More Articles From: