Abstract
We have been challenged by Peter Chapman to consider the implication of hormesis for both ecotoxicology and ecological risk assessment. A consideration of his proposal led to the following observations and comments. I echo his comments related to the need for experimental designs and statistical tools that accommodate and address hormesis. I expand on his comments related to the basic question of how adverse responses should be defined for hormetic concentration–response patterns for both individual species and populations. Finally, I reflect on the notion of the implication of incorrectly detecting or not detecting hormesis in an ecosystem.