# Renkonen similarity index

The Renkonen similarity index (P), is a measure of dissimilarity between two communities (sites), based on relative (proportional) abundances $p_i = n_i/\sum{n_i}$ of individuals of composite species. It was developed by the botanist Olavi Renkonen and published in 1938.[1]

The codomain of this distance function ranges from 1 (identical proportional abundances) to 0 (no taxa shared).