Reason from a business question to the action unit marketing can actually change: campaign, channel, audience, creative, offer, bid, or budget. Pick an objective metric and guardrails that match that decision instead of optimizing a number that cannot guide action.

Trace a customer path from impression and reach to click, visit, lead, order, or conversion. Keep the unit and denominator straight for CTR, conversion rate, frequency, and cost-per metrics so comparisons are meaningful.

Connect conversions to revenue, average order value, gross margin, contribution margin, CPA, CAC, ROAS, and payback. Decide when a campaign that drives sales is still not profitable enough to scale.

Apply the previous explanations in a guided problem.

Work with retention, churn, repeat purchase rate, cohorts, customer lifetime value, and LTV:CAC. Use these metrics to reason about lifecycle decisions such as onboarding, loyalty offers, winback, and how much acquisition spend is sustainable.

Separate observed credit from causal impact by asking what would have happened without the marketing. Use lift, incremental conversions, incremental revenue, incremental margin, and iROAS to judge whether a channel or campaign truly deserves more budget.

Apply the previous explanations in a guided problem.

Check your understanding with a short quiz.

Review this chapter with practice based on your mistakes.