Normalized Discounted Cumulative Gain (NDCG)
Definition
NDCG evaluates the relevance and order of a search result list.
A ranking measure that weights graded relevance of higher-ranked results more strongly and normalizes to an ideal rank.
Simply explained
Especially relevant hits should be at the top; the list is compared with an ideal order.
Why it matters in practice
NDCG evaluates both the relevance and position of search hits. This allows comparing rankings based on graded quality judgments.
Example from business
A search rates highly relevant hits at rank one more strongly than at rank ten.
Limits and pitfalls
- Report NDCG without cut-off, relevance scale, or handling of ties.
Origin & history
DCG and NDCG were established in the early 2000s for information retrieval.
Use in mid-sized companies
- Possible example: A search team rates hits by their relevance and compares which ranking places particularly helpful results further forward.
Frequently asked questions
What does Normalized Discounted Cumulative Gain mean?
A ranking measure that weights graded relevance of higher-ranked results more strongly and normalizes to an ideal rank.
Which mistakes should be avoided?
Report NDCG without cut-off, relevance scale, or handling of ties.
Sources
Source checked on 10.10.2026. Editorial application examples are hypothetical; no proof of real customer results.
Editorially reviewed on: