Effects of Message Completeness and Source Expertise in Online Health Discussion Boards

Abstract

This study examines the effect of message completeness (presence vs. absence of an explanation), source expertise (doctor vs. layperson), and task importance (low vs. high) on message elaboration, perceived message credibility, and behavioral intentions in the context of an online health discussion board (N = 499). Results from an experiment show that message completeness increased perceived message credibility, which in turn increased intentions to follow and share the advice. The main effect of source expertise on message elaboration, perceived message credibility, and behavioral intentions was not observed. Neither the effect of message completeness nor the effect of source expertise varied with the level of task importance. These findings suggest that the presence of an explanation may be key to establishing credibility in the context of an online health discussion board.