Allotaxonometry

A suite of instruments for comparing two ranked lists — word frequencies, name counts, topic distributions — across time, place, or any declared dimension. Includes the allotaxonometer and wordshift.

Allotaxonometer

The allotaxonometer measures rank-turbulence divergence (RTD) between two ranked lists and produces a contribution breakdown: which elements shifted the most, and in which direction. The visual output is an allotaxonograph — a mirror plot showing the top drivers of the divergence.

The core calculations are implemented in allotaxonometer-core, a Rust crate that handles the RTD computation. The web instruments call this crate via WebAssembly.

Wordshift

Wordshift decomposes the difference in average word score (sentiment, frequency, or any per-word signal) between two text collections into word-level contributions — which words drove the change, through increased or decreased usage, and whether they pulled the score up or down.