MQL vs SQL

Because that conversion rate is a lead-quality measurement you already have. It is computed, it lives in your CRM, and it is the closest thing to ground truth that exists before revenue.

And it goes nowhere. It gets reported upward in a board deck and it never travels back to the form, the variant, the campaign, or the field that produced the lead — which is the exact shape of the problem one practitioner described better than any vendor has:

• Compute the rate per source, per campaign, and per form, not company-wide. The company-wide number is a vanity metric; the per-form number is a decision.
• Use SQL acceptance as your interim outcome when deals take too long to wait for — see time to disposition.
• Write the disposition back onto the submission record, not just into the CRM report. That is what makes it usable by anything upstream.
• Track the rejection reasons, not just the rate. “Not a real person”, “wrong company size” and “bad timing” are three different problems with three different fixes, and only one of them is a spam problem.

Enormous amounts of time go into agreeing what an MQL is. Almost none goes into asking whether the rate differs between the form on the pricing page and the form on the blog — which it does, usually by a lot, and which is immediately actionable in a way the definitional argument never becomes.

The definition only has to be stable. It does not have to be right. A consistently applied imperfect definition, measured per form, tells you more in a month than a perfect definition applied to a company-wide average tells you in a year.