TREC-like evaluations do not consider topic ease and difficulty. However, it seems reasonable to reward good effectiveness on difficult topics more than good effectiveness on easy topics, and to penalize bad effectiveness on easy topics more than bad effectiveness on difficult topics. This paper shows how this approach leads to evaluation results that could be more reasonable, and that are different to some extent. I provide a general analysis of this issue, propose a novel framework, and experimentally validate a part of it.