index_simpson: Simpson Dominance Index

In tabula: Analysis and Visualization of Archaeological Count Data

Simpson Dominance Index

Description

Simpson Dominance Index

Usage

index_simpson(x, ...)

## S4 method for signature 'numeric'
index_simpson(x, evenness = FALSE, unbiased = FALSE, na.rm = FALSE, ...)

Arguments

x	A numeric vector of count data (absolute frequencies).
...	Currently not used.
evenness	A numeric scalar: should evenness be computed?
unbiased	A logical scalar: should the bias-corrected estimator be used?
na.rm	A numeric scalar: should missing values (including NaN) be removed?

Details

The Simpson index expresses the probability that two individuals randomly picked from a finite sample belong to two different types. It can be interpreted as the weighted mean of the proportional abundances. This metric is a true probability value, it ranges from 0 (all taxa are equally present) to 1 (one taxon dominates the community completely).

This is a dominance index, so that an increase in the value of the index accompanies a decrease in diversity.

Value

A numeric vector.

Author(s)

N. Frerebeau

References

Simpson, E. H. (1949). Measurement of Diversity. Nature, 163(4148), 688-688. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1038/163688a0")}.

See Also

Other alpha diversity measures: index_ace(), index_baxter(), index_berger(), index_boone(), index_brillouin(), index_chao1(), index_chao2(), index_hurlbert(), index_ice(), index_margalef(), index_mcintosh(), index_menhinick(), index_shannon(), index_squares(), observed()

tabula documentation built on April 4, 2025, 5:09 a.m.