Sufficient similarity is a 20th-century para-legal concept used in the chemical industry for toxicological studies.[1][2] The term was first employed in a restricted sense to assess surrogacy of chemical mixtures by the EPA, and has descended from there into the scientific argot.[2][3]
The concept is somewhat nebulous, and statistics are involved.[4] A group of America researchers in 2018 posed themselves the question how similar must a product be in order to be well-represented by the tested reference sample?[5] Because the concept was derived from the EPA, chemical similarity and biological similarity are equally important.[5] The concept is employed "so that safety data from the tested reference can be applied to untested materials,"[5] because "when toxicity data are not available for a chemical mixture of concern, US EPA guidelines allow risk assessment to be based on data for a surrogate mixture considered “sufficiently similar” in terms of chemical composition and component proportions."[1]
^ abStork, Leanna G.; Gennings, Chris; Carter, Walter H.; Teuschler, Linda K.; Carney, Edward W. (2008). "Empirical evaluation of sufficient similarity in dose—Response for environmental risk assessment of chemical mixtures". Journal of Agricultural, Biological, and Environmental Statistics. 13 (3): 313–333. doi:10.1198/108571108X336304. S2CID120503027.
^Feder, Paul I.; Ma, Zhenxu J.; Bull, Richard J.; Teuschler, Linda K.; Rice, Glenn (2009). "Evaluating Sufficient Similarity for Drinking-Water Disinfection By-Product (DBP) Mixtures with Bootstrap Hypothesis Test Procedures". Journal of Toxicology and Environmental Health, Part A. 72 (7): 494–504. doi:10.1080/15287390802608981. PMID19267310. S2CID23974025.