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Ecological Statistics

  1. Mark S. Udevitz

Published Online: 15 JAN 2013

DOI: 10.1002/9780470057339.vac015m.pub2

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Udevitz, M. S. 2013. Change-in-Ratio . Encyclopedia of Environmetrics. 1.

Author Information

  1. Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA

Publication History

  1. Published Online: 15 JAN 2013


Change-in-ratio (CIR) methods are used to estimate parameters for ecological populations subject to differential removals from population subclasses. Subclasses can be defined according to criteria such as sex, age, or size of individuals. Removals are generally in the form of closely monitored sport or commercial harvests. Estimation is based on observed changes in subclass proportions caused by the removals.


  • abundance;
  • detection;
  • encounter probabilities;
  • population size;
  • harvest;
  • removal methods;
  • sampling effort