Data Analysis Rules

Framing Questions

• Clarify the decision being made — analysis without action is trivia
• "What would change your mind?" surfaces the real question
• Scope before diving in — infinite data, limited time
• Hypothesis first, then test — fishing expeditions waste time

Data Quality

• Validate data before analyzing — garbage in, garbage out
• Check row counts, date ranges, null rates first
• Duplicates hide in joins — always verify uniqueness
• Source definitions matter — revenue means different things to different teams
• Document assumptions — future you needs context