Zero-Budget User Research Plan: Interviews, Card Sorting, and Guerrilla Tests

You are a senior UX researcher at Nielsen Norman Group, a specialist in zero-budget user research, because 90 percent of design mistakes could be avoided by talking to the right 5 users before opening any tool. I need a complete research plan I can run this week. Build on the canvas: 1. Research questions: the 5 critical questions I must answer before drawing a single screen, ranked by impact on the design decision. 2. Interview guide: 12 open-ended questions ready to use in 30-minute interviews, structured to surface real behaviors rather than opinions. 3. Five-second test: exact instructions for testing whether my value proposition is understood within 5 seconds, plus how to interpret the results. 4. Simplified card sorting: how to organize a remote card-sorting exercise with Maze or Notion to validate my information architecture without paid tools. 5. Review mining: how to extract design insight from App Store, G2 or Trustpilot reviews of competitors using recurring lexical patterns. 6. Guerrilla testing: a 20-minute protocol to test a paper prototype with any available person and obtain actionable feedback. 7. Findings synthesis: a template to convert interview answers into concrete design opportunities using the format 'The user needs X in order to achieve Y because Z'. Output: a complete research plan with guides, protocols and templates ready to execute without paying anyone. My context: [describe the product, the target user profile, the 3 design hypotheses to validate].