R package propr. The bioinformatic evaluation of gene co-expression often begins with correlation-based analyses. However, this approach lacks statistical validity when applied to relative data, including those biological count data produced by microarray assays or high-throughput RNA-sequencing. As an alternative, Lovell et al propose a proportionality metric, phi, derived from compositional data analysis, a branch of math dealing specifically with relative data. In a subsequent publication, Erb and Nicodemus expounded these efforts by elaborating on another proportionality metric, rho. This package introduces a programmatic framework for the calculation of feature dependence using proportionality and other compositional data methods discussed in the cited publications.