Invisible Power: Newspaper News Sources and the Limits of Diversity

^ The last broad-based, systematic assessment of news source diversity was published by Sigal 10 years ago. • Culbertson's study of the veiling of news sources is almost as old.^ In the meantime, not only has the theoretical debate become more lively and more sophisticated, but substantial changes have taken place in the poUtical, organizational and commercial environments of the news industry. These changes call for general recalibration, on the order of Sigal's and Culbertson's studies, regarding the nature and extent of diversity of news sources and news channels.

[1]  M. Parenti Power and Pluralism: A View from the Bottom , 1970, The Journal of Politics.