Work out simpson diversity index instantly with clear inputs, formula shown and shareable results.
Sums the squared proportional abundances to give Simpson's dominance, then reports both the Gini-Simpson and reciprocal forms.
Simpson's index
D = sum(pi^2); Gini-Simpson = 1 - D; reciprocal Simpson = 1/D, which equals the effective number of dominant species
Simpson weights the commonest species more heavily, so it is less sensitive to rare species than Shannon.
The probability that two individuals drawn at random belong to different species.