Estimation of extra risk and benchmark dose in dose–response models

An important goal in quantitative risk/safety analysis of chemical toxins or pharmaceutical agents is determination of toxic risk posed by exposure to the agent.For purpose of assessing exposure risks, the extra risk function is defined as the risk above the background level corrected for non-response in the unexposed population.Our interest, in this paper, is in statistical methods for obtaining upper confidence limits on the extra risk and lower confidence limits on the dose level at which a certain benchmark risk is achieved.Existing method on the above problem is examined and several examples from literature are provided. In addition, a new method of obtaining the desired confidence intervals is investigated and the results are compared with those obtained by the existing method.