On the Representativeness Assumption in Prevalence Tests of Carcinogenicity

SUMMARY Conditions for the validity of the Hoel-Walburg and Peto tests, which compare dose groups with respect to tumour prevalence, are replaced by a more general condition, representativeness. A large carcinogenicity experiment provided a unique opportunity to assess empirically if this condition holds. Though representativeness was generally violated, neither the Hoel-Walburg nor the Peto tests were seriously distorted. Analytic considerations suggest that such robustness can occur in many situations.