R package “extr: Extinction Risk Estimation” Released on CRAN

On September 21, 2025, Professor Hiroshi Hakoyama of the Institute for Freshwater Biology, Nagano University, released his R package “extr: Extinction Risk Estimation” on the Comprehensive R Archive Network (CRAN).

This package implements a method for estimating extinction probabilities from population time-series data under the Wiener process with drift, and includes the newly proposed approach for constructing confidence intervals for extinction risk using the w–z method (Hakoyama, 2025, arXiv preprint).

The method enables accurate extinction-risk estimation even with limited data, providing a statistically rigorous framework for validating Population Viability Analysis (PVA) and supporting IUCN Red List assessments.

• CRAN page: https://cran.r-project.org/web/packages/extr/
• Project site (GitHub): https://hakoyamah.github.io/extr/