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Biological Assay

Environmental Health

  1. Brent A. Coull1,
  2. Louise M. Ryan2

Published Online: 15 SEP 2006

DOI: 10.1002/9780470057339.vab015

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Coull, B. A. and Ryan, L. M. 2006. Biological Assay. Encyclopedia of Environmetrics. 1.

Author Information

  1. 1

    Harvard University, MA, USA

  2. 2

    University of Harvard, MA, USA

Publication History

  1. Published Online: 15 SEP 2006


Biological assay (also called bioassay) refers to methods for characterizing the potency of a stimulus based on the outcome of its application to living organisms. Traditionally, statistical methods in bioassay have focused on the estimation of the relative potency of a standard and a test drug. In environmental health research, interest often focuses on characterizing the dose–response relationships between a health effect and one or more exposures. In this setting, bioassay plays an important role in the assessment of toxicity of potentially hazardous substances; such studies (a) confirm associations between health effects and environmental exposures observed in environmental epidemiological studies, (b) provide insight into biological mechanisms underlying exposure effects, and (c) yield dose–response information that is vital for regulatory decision making. Such studies play a large role in carcinogenesis, teratogenesis, mutagenesis, and other toxicity studies, with statistical methods for analyzing bioassay data varying depending on the type of study. This article illustrates some general issues in the analysis of bioassay data by focusing on the simple setting of a rodent toxicological bioassay.