Every paid channel can be made to look good if you pick a shallow enough metric. Impressions flatter reach. Clicks flatter creative. Cost per lead flatters the form. None of them tell you whether the money produced revenue.
Move the measurement one step deeper
The useful question is not what a lead costs, but what a lead that a salesperson would actually want costs. Those two numbers can differ by an order of magnitude across channels that look identical on a cost-per-lead report.
- Tag every lead with its channel, campaign, and creative at capture
- Let sales mark qualification honestly, including the fast rejections
- Report cost per qualified opportunity, not cost per form fill
- Review at a cadence slow enough to be statistically real
Expect the ranking to change
The first time a team sees spend ranked by qualified pipeline instead of lead volume, the ordering usually inverts. The cheapest leads are frequently the least serious, and the channel that looked expensive turns out to be the one producing customers.
You cannot optimise toward revenue using a metric that stops at the form.
The tracking work is unglamorous and takes a fortnight. It is also the difference between a marketing budget you can defend and one you can only describe.