Mean Reciprocal Rank
Mean reciprocal rank of the first relevant document; MRR; MRR1
The Reciprocal Rank (RR) information retrieval measure calculates the reciprocal of the rank at which the first relevant document was retrieved. RR is 1 if a relevant document was retrieved at rank 1, if not it is 0.5 if a relevant document was retrieved at rank 2 and so on. When averaged across queries, the measure is called the Mean Reciprocal Rank (MRR).
Mean Reciprocal Rank is associated with a user model where the user only wishes to see one relevant document. Assuming that the user will look down the ranking until a relevant document is found, and that document is at rank n, then the precision of the set they view is 1/n, which is also the reciprocal rank measure. For this reason, MRR is equivalent to Mean Average Precision in cases where each query has precisely one relevant document. MRR is not a shallow measure, in that its value changes whenever the required document is moved,...