Information retrieval systems are compared using evaluation metrics, with researchers commonly reporting results for simple metrics such as precision-at-10 or reciprocal rank together with more complex ones such as average precision or discounted cumulative gain. In this paper, we demonstrate that complex metrics are as good as or better than simple metrics at predicting the performance of the simple metrics on other topics. Therefore, reporting of results from simple metrics alongside complex ones is redundant. Categories and Subject Descriptors H.3.4 [Information Storage and Retrieval]: Systems and software