title: Absence of effect in stochastic processes: its influence on test validation and test use.
abstract: Negativity in stochastic processes presents problems in interpretation because it is never possible to attain an absolutely adequate assurance of safety with such processes. Thus, it is extremely difficult to have complete confidence in the utility of validation studies of new methods in comparison to those that are accepted to be well established, especially when these processes are stochastic in the statistical sense of this term. The regulatory scientist who must make decisions on the basis of available evidence, therefore, has to make a number of assumptions in dealing with negativity. It is important to review the validity and usefulness of these assumptions from time to time to ensure that they cannot be replaced by improved methodology in the light of new scientific knowledge.
authors.affiliation: Toxicology Research Division, Bureau of Chemical Safety, National Health and Welfare, Ottawa, Ontario, Canada.
authors.forename: D B
authors.initials: DB
authors.lastname: Clayson
mesh_terms: D000818:Animals; D015197:Carcinogenicity Tests; D002273:Carcinogens; D011237:Predictive Value of Tests; D012306:Risk; D013269:Stochastic Processes
chemical_list: D002273:Carcinogens