Use Simpson Evenness when you need to compute Simpson evenness as (1 / D) divided by species count from a Simpson concentration index strictly between zero and one. Enter Simpson index and Species count using the definitions and units below so the result can be reproduced.

Simpson index

A finite measured or assumed value.

Species count

An integer count or setting greater than or equal to 1, expressed in species.

The published tool contract uses this rule: Compute Simpson evenness as (1 / D) divided by species count from a Simpson concentration index strictly between zero and one.

Simpson evenness

The calculated simpson evenness.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.

Retain the original Simpson index and Species count values and their units alongside the result. Pielou Corrected is useful when you instead need to compute corrected Pielou evenness as natural Shannon entropy divided by the natural logarithm of the species count, returning exactly zero when entropy is zero. Simpson Reciprocal provides another view by helping you compute the reciprocal Simpson diversity as one divided by the Simpson concentration.

• Pielou Corrected

  Compute corrected Pielou evenness as natural Shannon entropy divided by the natural logarithm of the species count, returning exactly zero when entropy is zero.

• Simpson Reciprocal

  Compute the reciprocal Simpson diversity as one divided by the Simpson concentration.

• Pielou Evenness

  Compute Pielou evenness J = H / ln(S) from the Shannon index and species count, requiring at least two species.