Topics
Distinguish between stmt of user need (topic) & system data structure (query)
- topic gives criteria for relevance
- allows for different query construction techniques
TREC topics are NOT all created equal
- 1-150: very detailed, rich content
- 151-200: method of topic creation resulted in focused, easy topics
- 201-250: single sentence only
- 301-450: title is set of hand-picked keywords