Improving ranking algorithms for information retrieval. The ranking algorithms operate on search results obtained from a search engine. Input information including information describing a first ranking algorithm, a first score associated with the first ranking algorithm, a second ranking algorithm, a second score associated with the second ranking algorithm, and causal information relating a difference between the first ranking algorithm and the second ranking algorithm with a difference between the first score and the second score is received. An optimizing algorithm is applied to the received input information to identify an optimal ranking algorithm having an optimal score. The optimal ranking algorithm is defined by a plurality of parameters and a plurality of weights associated with the plurality of parameters.