core practice · coding problem
Browse vs search metrics
Discovery feed: which metric — CTR, dwell time, or nDCG@10? Pick one for homepage browse, one for keyword search, justify in one line each.
The mechanism
A search system is a pipeline, not a scoring function: analyze -> inverted index -> cheap candidate retrieval -> expensive reranking -> serve. The first stage decides what the good ranker is ever allowed to see, so recall lost there cannot be recovered later. Autocomplete is a separate prefix index with its own latency budget, not a query against the main index.
Expected evidence
Browse: dwell/engagement; search: nDCG/precision@k.
Try this drill in the practice workspace →
Hints when you need them
- Discovery has weak intent.
- Keyword search has explicit relevance labels.