sub-question decomposition

**Sub-question decomposition** is the **method of breaking a complex query into smaller answerable sub-questions and then combining the results** - decomposition improves retrieval focus and reasoning reliability for multi-part tasks. **What Is Sub-question decomposition?** - **Definition**: Query planning step that identifies independent or dependent sub-questions. - **Workflow Pattern**: Decompose, retrieve and answer each sub-question, then synthesize final response. - **Task Fit**: Effective for comparison, multi-hop reasoning, and analytical aggregation tasks. - **System Requirement**: Needs robust coordination across sub-results and conflict resolution. **Why Sub-question decomposition Matters** - **Retrieval Precision**: Smaller queries retrieve more targeted evidence than one broad query. - **Reasoning Control**: Reduces cognitive load and error propagation in complex tasks. - **Transparency**: Intermediate answers make solution path easier to verify. - **Coverage Improvement**: Ensures each required aspect of a question is explicitly addressed. - **RAG Accuracy**: Structured synthesis from validated sub-answers lowers hallucination risk. **How It Is Used in Practice** - **Planner Stage**: Generate sub-question graph with dependency ordering. - **Parallel Retrieval**: Resolve independent sub-questions concurrently when latency budget allows. - **Synthesis Guardrails**: Reconcile contradictions and cite evidence per sub-answer. Sub-question decomposition is **a core strategy for complex RAG reasoning workflows** - explicit query breakdown improves evidence targeting, answer completeness, and verification quality.