The influence of design characteristics on statistical inference in nonlinear estimation: a simulation study based on survival data and hazard modeling

摘要

This paper describes the influence of design characteristics on the statistical inference for an ecotoxicological hazard-based model using simulated survival data. The design characteristics of interest are the number and spacing of observations (counts) in time, the number and spacing of exposure concentrations (within C_(min) and C_(max)), and the initial number of individuals at time 0 in each concentration. A comparison of the coverage probabilities for confidence limits arising from the profile-likelihood approach and the Wald-based approach is carried out. The Wald-based approach is very sensitive to the choice of design characteristics, whereas the profile-likelihood approach is more robust and unbiased. Special attention is paid to estimating a parametric no-effect concentration in realistic small-sample situations since this is the most interesting parameter from an environmental protection point of view.