Semantic Index

Evaluation

Metrics

nDCG@k:

• "The value of NDCG is determined by comparing the relevance of the items returned by the search engine to the relevance of the item that a hypothetical "ideal" search engine would return.
• "The relevance of result is represented by a score (also known as a 'grade') that is assigned to the search query. The scores of these results are then discounted based on their position in the search results -- did they get recommended first or last?"

MRR@k:

• "Mean reciprocal rank quantifies the rank of the first relevant item found in the recommendation list."

MAP@k:

• "Mean average precision averages the precision@k metric at each relevant item position in the recommendation list.

Resources:

• Evaluating recommendation metrics
• Math Walkthrough