Besides, MAP is roughly the average area under the precision-recall curve for a set of queries (Christopher et al., 2008).
formally, given a concept c, a set of m stocks {o i } m i=1 and n data sources and each D i j is a sequence of words w 1 , w 2 ...w |D i j | , we assume the relevant stocks of the concept are revealed in the data sources (e.g.