What is the MAP metric?

MAP (Mean Average Precision) is a quality metric often used in information retrieval and recommendation systems. It measures the average precision across all queries or objects, considering the order of relevant items in the results.

Working principle:

• For each query, Average Precision (AP) is calculated — the average precision at the positions where relevant results are found.
• Then, the mean of AP is taken over all queries.

MAP reflects the quality of ranking well because it considers not only the presence of relevant elements but also their position in the list.

Example: if you have 3 relevant documents in the top-5 results, MAP will consider how high they are ranked, not just their presence.