The hypothesis that "ideas often flow from radio and print to opinion leaders and from these to the less active sections of the population" has been tested in several successive studies. Each study has attempted a different solution to the problem of how to take account of interpersonal relations in the traditional design of survey research. As a result, the original hypothesis is largely corroborated and considerably refined. A former staff member of the Bureau of Applied Social Research at Columbia University, the author is now on leave from his post as assistant professor of sociology at the University of Chicago and is currently guest lecturer in sociology at the Hebrew University in Jerusalem.