A0387
Title: Comparing methods for determining power priors based on different congruence measures
Authors: Jing Zhang - Miami University (United States) [presenting]
John Bailer - Miami University (United States)
Ainsley Helling - Miami University (United States)
Abstract: A Ceriodaphnia dubia (C. dubia) reproduction test is often used to evaluate the sublethal toxicity of water effluents or chemicals. In a C. dubia reproduction test, organisms are exposed to varying concentration levels of the toxicant or other adverse treatment and the number of young after a given experiment period is recorded. The reproduction response is modelled as a function of the concentration, and the concentration associated with specified levels of estimated adverse effect is used in risk management to analyse the experiment outcomes. While aquatic toxicity analyses often focus on outcomes from the current experiment, laboratories commonly have a history of conducting such experiments using the same species, following a similar experimental protocol. So it is often reasonable to believe that the same underlying biological process generates the historical and current experiments. In the present study, using a calibrated power prior approach is proposed to incorporate historical control outcomes as prior input and compare the behaviour of the method when different congruence measures are used to determine the amount of historical input that will be incorporated. Simulation results show that three of the congruence measures show attractive features in practice. Using the calibrated power priors would improve precision and the bias of the potency estimates.
