What is influencer marketing attribution and why is it hard to measure?

Why influencer marketing attribution is genuinely hard — explained for CFOs: The multi-touch problem: a customer might see 3 creator posts, then a Google ad, then search your brand name and convert. Last-click attribution gives 100% credit to Google. Creator gets zero credit despite influencing the decision. The time lag: brand awareness from influencer content builds over weeks. A viewer sees your Reel on October 1 and buys on November 15 — the purchase looks like direct traffic. Platform walled gardens: Instagram doesn't share viewer identity with your analytics. You see views but not who viewed and later converted. Solutions that help: (1) Discount codes: direct attribution at point of sale. (2) UTM links: tracks click-to-conversion for viewers who click. (3) Lift measurement: compare sales in creator's primary city vs a comparable city that wasn't targeted. (4) Survey new customers: "how did you first hear about us?" gives directional data even if imperfect. No method is perfect — the goal is directional evidence, not forensic proof.