Difference between the incidence of an adverse effect in a treated group (of organisms or a group of exposed humans) and a control group (of the same organisms or the spontaneous incidence in humans)
International Union of Pure and Applied Chemistry IUPAC, Glossary for Chemists of Terms Used in Toxicology, Prepared for publication by J.H. Duffus, NC., USA 1993. http://www.inchem.org/documents/harmproj/harmproj/ harmproj1.pdf & http://old.iupac.org/reports/1993/6509duffus/c.htm l, (IUPAC/ Tox - Amer) {107}