“Overall, Ritchie provides an excellent introduction to Shannon's theories of communication and the associated ideas concerning information.” – Library Quarterly SERIES QUOTE: “The second volume in the series is titled information and the third volume is Gatekeeping. Taking their lead from Chaffee, both Ritchie and Shoemaker carefully explicate the concepts which focus their texts. As is the first volume in the series, these are well-thought out, succinct, and very readable volumes. Additional titles are planned…. If the standards set by these three are continued, this promises to be an exciting series which provides clarity and focus to the study of communication.” – ETC: A Review of General Semantics Challenging, intriguing, complex–defining information has occupied many of the best minds in the field of communication for half a century. Information seeks to summarize and resolve the difficult issues associated with this endeavor. Ritchie succinctly explains the distinctions among the myriad definitions/understandings of information and why these distinctions are important. Providing a definition for information, he then explores how the concept of information can connect various aspects of the communication process in a coherent way. This analysis ranges across several levels of conceptual usage: technical meaning in engineering; the complex meanings of information; and its metaphorical usage by communication theorists.
Chapter 4: Redundancy: How Structure Affects Variety
Redundancy: How Structure Affects Variety
H measures the variety among the elements in any set. Chapter 3 introduced two ways to calculate H, Hmax and Hobs. In Chapter 4, these two quantities will provide a basis for estimating the [Page 33]degree to which structural constraints on the way a code uses its elements reduces the amount that can be communicated by using the code. Hmax measures the maximum variety that would be observed if all elements appeared with equal probability, and Hobs measures the variety of actual observations: The difference between these two quantities is redundancy, the reduction in the efficiency of the code due to constraints on the use of its elements. Redundancy is useful for analyzing the trade-off between efficiency ...