# Topic Difficulty: Collection and Query Formulation Effects

> Research article (ACM Transactions on Information Systems, 2021) · cited 29× · AI/ML

**Wikidata**: [openalex:W3198734960](https://www.wikidata.org/wiki/openalex:W3198734960)  
**Source**: https://4ort.xyz/entity/topic-difficulty-collection-and-query-formulation-effects