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Why your best campaign by leads might be your worst by sales

Cost per lead can crown the wrong campaign. How to give leads a value from your CRM and move Google and Meta bidding towards sales, in safe stages.

By Gareth Puckey Updated 7 min read Marketing measurement

In this guide
  1. Why the campaign with the cheapest leads can lose on sales
  2. What Google and Meta optimise towards
  3. Giving leads a value: CRM stages, proxy values and value rules
  4. Google Ads: moving from Target CPA to value bidding safely
  5. Meta: switching lead ads to Conversion Leads
  6. The plumbing: offline imports and upload hygiene
  7. Judging success: cost per qualified lead, cost per sale and ROAS
  8. FAQ

If your bidding treats every form fill as equally valuable, it will look for the cheapest form fills, and a cost per lead figure can’t tell you whether any of those people bought. So the campaign that wins on cost per lead can be the one that loses on cost per sale. The fix is to send sales stages back from your CRM, give them values, and move bidding towards them one step at a time.

Why the campaign with the cheapest leads can lose on sales

An ad platform optimises towards whatever you tell it counts as a conversion. If that’s a form submission, it has no way to tell a serious enquiry from someone who was never going to buy. It just finds more form submissions at the lowest cost it can.

Your CRM is where you can see what happened next. I’ve connected 7 CRMs so sales can be traced back to the marketing that produced them, because without that link every lead looks the same in an ad report.

Illustrative example, not real data.

Campaign A Campaign B
Spend £1,000 £1,000
Leads 50 20
Cost per lead £20 £50
Qualified leads 5 10
Cost per qualified lead £200 £100
Sales 1 4
Cost per sale £1,000 £250

On a lead report, Campaign A looks two and a half times better. Follow the same leads through the CRM and Campaign B produces sales at a quarter of the cost. Cut B’s budget because its cost per lead is high and you cut the campaign that’s selling.

What Google and Meta optimise towards

Google renamed its main strategies from June 2026. “Maximise conversions with a Target CPA” is now “Target CPA”, and “Maximise conversion value with a Target ROAS” is now “Target ROAS”. Google says the behaviour hasn’t changed (Google Ads Help).

Maximise conversion value bids to get the most total conversion value from your budget, and you decide what that value is (revenue or margin, for example) through conversion values. With no target ROAS set, it tries to spend your full average daily budget (Google Ads Help).

The same page says it ignores existing bid adjustments. That matters to me, because I set monthly bid adjustments (device, age, gender, location and schedule) from 180 days of results, with a dry run first. On a campaign using Maximise conversion value, that work won’t be used, so check the strategy before you spend time on adjustments.

On Meta, the equivalent choice is between the standard Leads goal and Conversion Leads, covered in the Meta section below.

Giving leads a value: CRM stages, proxy values and value rules

Pick one stage to bid on

Google’s guidance for CRM stages is to bid to one funnel stage only, “either qualified lead or converted lead”, with a separate conversion action for each stage (Google Ads Help). Set the stage you’re bidding on as Primary and the others as Secondary. If form fills sit in the same goal as qualified leads, bidding can keep chasing cheap forms.

Give each stage a value

For Target ROAS or Maximise conversion value, Google’s advice is to “upload all conversions and assign values” (Google Ads Help).

If you don’t know the sale value at the qualified stage, my recommendation is a consistent proxy. One simple version is your average sale value multiplied by the share of qualified leads that become sales. It won’t be exact, but it gives bidding a reason to prefer a qualified lead over a raw form fill.

Google says not to backfill historical values, so start uploading from now (Google Ads Help).

Use conversion value rules sparingly

Conversion value rules change both the value you see in reports and the value Smart Bidding uses. They can be based on audience, location or device, with one primary and one secondary condition per rule. Google also warns that geography and device are already bidding signals, so rules on those may add little (Google Ads Help). I’d only add one where you have clear CRM evidence that a segment’s leads are worth more.

Google’s lead generation guidance is to switch in stages (Google Ads Help). In order:

  1. Bid on qualified leads with Target CPA. Make the qualified lead stage the Primary conversion and let the campaign settle on it.
  2. Upload values before you change strategy. Google suggests “3 weeks or 1-2 conversion cycles, whichever is longer” of value data before value bidding (same source).
  3. Check volume. Target ROAS needs at least 15 conversions in the last 30 days on Search, and conversion values need to be set first (Google Ads Help).
  4. Check the budget. Under Target ROAS, Google says to be comfortable with daily spend up to 2x your average daily budget (same source).
  5. Switch to value bidding, then judge it on cost per sale and ROAS from the CRM.

Allow for Google’s August 2026 change

Google changed its bidding systems from 17 August 2026 and says budget-limited Target CPA and Target ROAS campaigns may see temporary swings. It also lists a Bid Target Adjustment Tool, available from 6 July 2026 (Google Ads Help). If a budget-limited campaign changed strategy around that date, I’d be careful about comparing its before and after figures.

Meta: switching lead ads to Conversion Leads

Conversion Leads is Meta’s alternative to the standard Leads goal. It works towards a target CRM stage that you upload, and it only works with Instant Forms. Meta suggests these eligibility criteria (Meta for Developers):

  • at least 200 leads a month
  • the target CRM stage reached within 28 days of the lead
  • that stage converting between 1% and 40% of leads
  • CRM data uploaded at least daily
  • time to value of about one month

So a weekly upload batch, or a stage that usually takes longer than 28 days to reach, falls outside Meta’s suggested daily uploads and 28-day window (Meta for Developers).

Meta says ads using this setup “saw an average 15% lower cost per quality lead” and a 44% higher rate of leads becoming quality leads compared with the standard Leads goal (Meta for Business). Those are Meta’s own figures and the methodology isn’t shown, so I’d treat them as a reason to run your own test.

If your Meta leads come through a website form, this goal doesn’t apply, and the route for those leads is covered in Meta Conversions API for lead generation.

The plumbing: offline imports and upload hygiene

Google offline imports

Conversions matched by GCLID (Google click identifier) can be uploaded up to 90 days after the click (Google Ads Help). A sale that closes after that can’t be matched back, and a lead saved without its GCLID can’t be matched by a GCLID-based import. Capture the click ID with the form and store it against the lead in your CRM, as set out in Getting offline sales back into Google Ads.

Mistakes that undo the switch

  • Switching to Target ROAS too early. Fewer than 15 conversions in 30 days, or switching on the same day values start, leaves bidding without the value data Google asks for (Google Ads Help, Google Ads Help).
  • Stale or patchy uploads. Missing GCLIDs or lead IDs, weekly batches, or a Meta stage converting above 40% of leads all take you outside the guidance above (Google Ads Help, Meta for Developers).

Judging success: cost per qualified lead, cost per sale and ROAS

Once the stages are flowing, change what you report. I’d lead with cost per qualified lead, cost per sale and ROAS from the CRM, and keep cost per lead as a diagnostic for problems such as a broken form.

The same applies to the routine checks. A weekly search term report lists terms that spent without converting, but it’s only as useful as the conversion it’s measured against. Count qualified leads and it starts pointing at the terms that bring in poor enquiries.

Keep the report short enough that people read it. My monthly GA4 reports for 36 websites are drafted automatically, then checked by a person before they’re sent, and the layout is covered in The one-page GA4 report people actually read.

FAQ

How many conversions do I need for Target ROAS?

On Search, at least 15 conversions in the last 30 days, with conversion values set first (Google Ads Help).

How long after a click can I upload a CRM conversion to Google Ads?

Up to 90 days for GCLID-based conversions (Google Ads Help). Anything older can’t be matched to the click.

Does Meta’s Conversion Leads goal work with website forms?

No. It only works with Instant Forms, and Meta suggests at least 200 leads a month for eligibility (Meta for Developers).

For the wider picture, see my guide to marketing measurement.

7 sources, all opened and checked
  1. About Maximise conversion value bidding, Google Ads Help
  2. Bid strategy name changes and value bidding for lead generation, Google Ads Help
  3. About Target ROAS bidding, Google Ads Help
  4. About conversion value rules, Google Ads Help
  5. Importing CRM conversions by funnel stage, Google Ads Help
  6. Conversion Leads integration, Meta for Developers
  7. Advantage+ leads, Meta for Business

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