CTR (click-through rate)

CTR is clicks divided by impressions: the share of people who saw an ad and acted on it. It measures message-to-audience fit, which is a real and useful thing to know, but it is an input metric and not a business result. An ad can win the click and lose everything after it.

On Google, CTR does more than describe interest — expected click-through rate is a component of ad rank, so a higher CTR lowers what you pay per click for the same position. That gives it genuine compounding value: relevance work shows up twice, once as more clicks and again as cheaper ones. On Meta the mechanism is different but the direction is similar, since engagement affects delivery.

The trap is reading CTR without the step after it. A creative that lifts CTR from 1.2% to 2.4% halves your effective CPC, and if the traffic it attracted converts at half the rate, cost per order has not moved at all. Curiosity-driven hooks do exactly this: they promise something the landing page does not continue, and the additional clicks are people who were never going to buy. The CTR line improves, the CPA line does not, and the ad gets scaled because one of those two numbers is the one on the creative report.

Work it through. Ad A: 1.2% CTR, 3% conversion rate, $20 CPM. That is a $1.67 CPC and a $55.56 CPA. Ad B: 2.4% CTR, 1.4% conversion rate, same CPM. That is a $0.83 CPC and a $59.52 CPA. Ad B doubles CTR, halves CPC, and is slightly worse at the only thing that matters. On a report ranked by CTR it is the clear winner.

So always read CTR paired with conversion rate, and judge creative on cost per outcome. The pairing also diagnoses: high CTR with low conversion rate points at a mismatch between the promise and the page; low CTR with high conversion rate usually means the ad is under-selling something that works, and is worth more impressions rather than fewer.

Finally, do not compare CTR across accounts. It varies by placement, intent tier, industry, and format to a degree that makes cross-account comparison mostly noise — a 0.6% CTR on a cold prospecting video and a 9% CTR on a brand search term are not on the same scale. The comparisons that carry signal are an ad against its own history and against its siblings in the same auction context, which is also how creative fatigue becomes visible.