About a century after John Stuart Mill first suggested the importance of personal influence and the role of influential individuals and groups, several scholars have expounded on the topic of opinion leadership. Among them are Elihu Katz and Paul Lazarsfeld, who saw opinion leaders as different from other types of leaders in that they are not necessarily individuals with superior authority. Because they have been known to function as catalysts for changing knowledge, attitudes, and behavior, and because they have shown the ability to stimulate the diffusion of ideas, practices, and innovations, opinion leaders have been studied intensively in the fields of advertising, marketing, and communication.

Researchers have sought to determine who opinion leaders are and the extent of their influence over others in their respective ...