"Opinion leaders are not a group set apart, and ... opinion leadership is not a trait which some people have and others do not, but rather ... opinion leadership is an integral part of the give-and-take of everyday personal relationships" (Katz and Lazarsfeld 1955, p.33). Katz and Lazarsfeld see opinion leaders as people in certain segments of society that are interested in particular subjects who become, in effect, something like media experts on those subjects. It is these people, then, that absorb certain media messages and inform their friends, families, and peers. Opinion leaders are not necessarily traditional leaders in society, such as politicians and clergy and the like (although they can be). Rather, they are perceived experts in particular domains.
Lazarsfeld and Herbert Menzel note that opinion leaders are not found solely in the upper classes of society, but tend to be "evenly distributed through every class and population" (1974, p.97). Moreover, in the Decatur study of 1945, Katz and Lazarsfeld found that there was "very little overlap of leadership - a leader in one sphere was not especially likely to be influential also in another, unrelated, sphere" (Lazarsfeld and Menzel 1974, p.98). Therefore opinion leadership appears restricted to peer groups, at least on the surface. Cooks inform cooks on culinary issues, commuters inform commuters, and so on. Katz and Lazarsfeld refer to this concept as "horizontal opinion leadership" (1955, p.6). However, it would be simplistic to say that people only influence those that are exactly like themselves, and so there is always the presence of "vertical opinion leadership" that cannot be discounted in any conveyance of information - age and authority often play large roles (Katz and Lazarsfeld 1955, p.6).
One of the main points in discussing opinion leadership as it relates to functional theory and the Two - Step Flow model is that mass media communication does not reach the public in one giant wave. Rather, there are two steps in the process, and there is a trickle-down effect among subgroups of a population. The opinion leader, then, is the key to this model of communication.
Subgroups are collections of people that share similar traits or interests, and opinion leaders tend to be seen as those people who are both informed and are upholders of the "norms of a social system [or subgroup]" (Watson and Hall 1997, p.163). This is not to say that people may belong to one group only as they lead their daily lives. Rather, most people tend to belong to several groups at once, and consult different opinion leaders depending on the issue at hand (Katz and Lazarsfeld 1955, p.330-332). Katz and Lazarsfeld found in the Decatur study that opinion leadership exists in the realms of fashion, marketing, public opinion and movie attendance (1955, p.330-332), although it can be surmised that opinion leadership exists for every issue or decision one might encounter in day-to-day living.
For more specifics on what Katz and Lazarsfeld discovered about the concept of opinion leadership, click here.
