I ran 10 head-to-head prompt format battles — the structured one won 8/10 on specificity

I tested 10 common prompt engineering techniques against a structured JSON format across identical tasks (marketing plans, code debugging, legal review, financial analysis, medical diagnosis, blog writing, product launches, code review, ticket classification, contract analysis). The setup: Each task was sent to Claude Sonnet twice - once with a popular technique (Chain-of-Thought, Few-Shot, System Prompt, Mega Prompt, etc.) and once with a structured 6-band JSON format that decomposes every prompt into PERSONA, CONTEXT, DATA, CONSTRAINTS, FORMAT, and.