Evaluation for DataSet ClueWeb09B-Desc


Mean average precision for a set of queries is the mean of the average precision scores for each query: enter image description here

The DCG accumulated at a particular rank position p is defined as: enter image description here

Since result set may vary in size among different queries or systems, to compare performances the normalised version of DCG uses an ideal DCG. To this end, it sorts documents of a result list by relevance, producing an ideal DCG at position p IDCG@p, which normalizes the score: enter image description here

P@20 corresponds to the number of relevant results on the first 20 search results.