Why cost per lead beats cost per click
Two campaigns run side by side. One buys clicks at a third the price of the other, and on the monthly report it looks like the clear winner. Then you follow the clicks to the inbox: the "expensive" campaign produced most of the enquiries, and nearly all of the jobs. The cheap clicks were cheap for a reason — they belonged to people who were never going to buy.
This pattern shows up constantly, and it isn't bad luck. Ad platforms are obedient: they deliver exactly what you optimise for. Ask for cheap clicks and the algorithm will find the corners of the internet where clicks cost least — broad audiences, vague searches, idle thumbs. Ask for leads, with the tracking to prove them, and it hunts for the dearer, rarer click that belongs to someone with a job to be done.
Follow the money one level down
Cost per click answers a question nobody runs a business on. The questions that matter run one level down each time: what does an enquiry cost? What does a customer cost? What is that customer worth? A campaign can get steadily "worse" by the click and steadily better by every measure that reaches the bank account.
This is also how you catch the reverse failure — a campaign with flattering click prices quietly filling your inbox with tyre-kickers. Without cost per lead, and ideally cost per customer, the report can't tell the difference between an audience and a market.
What to change on Monday
Make sure every enquiry path is tracked back to its campaign — forms, calls, emails. Switch campaign objectives from traffic to conversions, so the algorithm is hunting the right animal. Then re-read last quarter's reports by cost per lead and watch the ranking of your campaigns reshuffle. The best-looking one is rarely still on top.
The cheapest click in the campaign is often the most expensive customer in the books.
None of this makes cost per click useless — it's a fine diagnostic for creative and targeting. It just makes a terrible finish line. Judge the spend on what it was for: enquiries from people you can actually help, at a price that leaves room to be worth it.