The Shannon index
, sometimes referred to as the Shannon-Wiener Index or the Shannon-Weaver Index,Krebs, Charles (1989) Ecological Methodology.
HarperCollins, New York. is one of several diversity indices
used to measure diversity in categorical data
. It is simply the Information entropy
of the distribution, treating species as symbols and their relative population sizes as the probability.
This article treats its use in the measurement of biodiversity
. The advantage of this index is that it takes into account the number of species and the evenness of the species. The index is increased either by having additional unique species, or by having a greater species evenness
The "Shannon-Weaver" name is a misnomer; apparently some biologists jumped to the conclusion that Warren Weaver
, author of an influential preface to the book form of Claude Shannon
's 1948 paper founding information theory
, was a cofounder of this theory. Weaver did play a crucial role in the rapid postwar development of information theory in a different way, however; as an influential early administrator of the Rockefeller Foundation, he ensured that the first information theorists received generous research grants. Norbert Wiener
had no hand in the index either, although his influential popularisation of cybernetics
was often conflated with information theory in the 1950s.
- <math>n_i</math> The number of......