Mean Reciprocal Rank (MRR)

1. Definition

MRR is a standard metric in ranking tasks, when there is a single correct answer per query.

For \(N\) queries, let's say you predict \(\text{rank}_i\) for the correct result (one which should ideally be ranked 1). Then,

\[ \text{MRR} = \frac{1}{N} \sum_{i=1}^{N} \frac{1}{\text{rank}_i} \quad \text{where} \quad \text{MRR} \in [0, 1] \]