Conversion Value Rules: The Advanced Attribution Lever

Conversion value rules are Google Ads' most under-used attribution lever. They let you tell Google Ads: "a purchase from a new customer is worth 2× a repeat purchase" or "a purchase from a mobile visitor in London is worth £50 more than a desktop visitor in Manchester." Smart bidding then optimises for total profitable conversion value, not raw revenue. This article walks through rule setup, new-customer-acquisition-cost framework, and the impact on smart bidding.

The Disconnect Between Tracking and Strategy

For too long, PPC management has been trapped in a binary of "did it convert or not?" Conversion tracking is the baseline; it tells you that a transaction happened. But in the modern eCommerce landscape, not all transactions are created equal. A £100 order from a customer who has bought from you twelve times already has a vastly different economic value than a £100 order from a brand-new acquisition.

By default, Google Ads treats these as identical. If your Target ROAS is 400%, smart bidding will happily spend £25 to acquire either. However, if your LTV (Lifetime Value) analysis shows that new customers are worth 3x their initial purchase value over 12 months, you should be willing to pay more for that first click. This is where conversion value rules come in-they are the bridge between your spreadsheet-based business logic and the real-time auction bidding algorithm.

What conversion value rules are (vs conversion tracking)

Conversion tracking captures what happened - a user bought a £120 basket, Google Ads records "one purchase, £120 value." Conversion value rules modify what Google Ads thinks that £120 is worth for the purpose of bidding decisions. The raw purchase value stays £120 in reports; smart bidding may treat it as £180 (new customer, +50%) or £60 (repeat, -50%) depending on the rules configured.

The rules apply at auction time. When Target ROAS or Max Conversion Value decides whether to bid £2.40 or £3.80 on a keyword, it uses the rule-adjusted expected value, not the raw value. This lets Google Ads chase profitability signals conversion tracking alone can't express - LTV differentials, margin variance, strategic geo priorities.

Under-used because most agencies stop at "install conversion tracking, set Target ROAS." Value rules are where smart bidding starts to reflect actual business economics, not raw eCommerce revenue. If you are still chasing raw ROAS, you are likely over-spending on brand-remarketing and under-funding your future growth.

The 4 rule types (audience, device, geo, conversion category)

Google Ads provides four primary dimensions for value adjustment. Each serves a specific strategic purpose in an advanced attribution framework.

1. Audience Rules

This is the most powerful lever in the set. By using your first-party data (uploading customer lists or using GA4 audiences), you can tell Google exactly who is worth more to you. At our UK eCommerce agency, we often use audience rules to apply a "Repeat Buyer Penalty". While "penalty" sounds harsh, it simply means we reduce the value of a repeat purchase so the algorithm stops lazily bidding on existing customers and starts hunting for new ones.

2. Device Rules

In many industries, mobile users convert at a higher rate but have a lower lifetime value than desktop users. This is common in B2B or high-ticket luxury items where the initial research is mobile, but the high-value transaction happens on a larger screen. If your data shows mobile customers spend 20% less over their lifetime, a -20% device rule ensures your mobile bids reflect that long-term reality.

3. Geo Rules

Geo rules are a "quick win" for businesses with varying operational costs. If shipping a large appliance to Northern Ireland costs £60 more than shipping to Birmingham, your margin is £60 lower. You can use a Geo rule to subtract a fixed £60 value from all conversions in high-cost shipping zones, forcing smart bidding to require a higher AOV to justify the bid in those locations.

4. Conversion Category Rules

Mostly used in hybrid accounts (e.g., lead gen and eCommerce combined). You might value a "Wholesale Inquiry" as 10x more valuable than a "Retail Purchase". Conversion category rules allow you to stack these priorities without having to manually change the underlying tracking code for every event.

New-customer vs repeat-customer value framework

The New-customer-acquisition-cost (NCAC) framework is a shift in mindset from campaign-level profitability to business-level growth. It treats a new customer's first purchase as worth more than a repeat purchase, because the new customer will (probably) generate additional purchases over their lifetime.

Why this matters for smart bidding: without NCAC, Target ROAS chases whichever click most efficiently converts - which is often a returning customer clicking a brand keyword. New-customer acquisition looks less profitable in the model, so bids compress and growth stalls. NCAC re-weights the equation so smart bidding chases the customers who move the business.

Calculating Your Multiplier

Typical multipliers depend on your vertical:

• Skincare/FMCG: High repeat rates. A new customer is often worth 2.5x - 3.5x their first purchase.
• Furniture/Luxury: Low repeat rates. Multiplier might only be 1.1x - 1.2x.
• Subscriptions: Very high LTV. Multipliers can reach 5x or higher if churn is low.

Use your CRM data or GA4 LTV reports to find this number. Do not guess. If your 12-month LTV is £240 and your average first order is £80, your multiplier is 3x.

Setting up new-customer-acquisition-cost (NCAC) rules

There are two implementation paths in Google Ads. We recommend Path A for precision, but Path B is an excellent starting point for smaller accounts.

Path A: The Audience-Based Adjustment

This is the "pro" way to handle NCAC. It involves creating a specific audience of people who have already bought from you and then applying a negative rule to that audience.

1. Define the Repeat Audience: Create a Google Ads remarketing list (via Audience Manager) for "All Converters - Last 540 Days". For more granularity, see our remarketing lists guide.
2. Create the Rule: Navigate to "Tools & Settings" > "Conversions" > "Value Rules".
3. Set the Condition: Condition = Audience. Select your "All Converters" list.
4. Set the Value: Adjustment = Multiply. Value = 0.5 (this effectively says a repeat customer is worth half as much as a new one).

Path B: New Customer Acquisition Goal

Google Ads now has a native "New Customer Acquisition" setting in campaign settings. Instead of de-valuing repeats, this *adds* a fixed bonus to new customers.

"If you value a new customer at £50 extra, Google Ads will add £50 to the reported conversion value of any user it identifies as 'new'. This is simpler but relies on Google's own (sometimes flawed) detection of who is a new vs returning customer."

Real-World Setup Examples

Rule combinations (stacking multiple rules)

Multiple rules can apply to the same conversion - they stack multiplicatively, not additively. This is a common point of confusion that can lead to "value evaporation" if not monitored.

Practical implication: stacking three or four rules can push adjusted values to extremes fast. A repeat customer on mobile in a low-priority geo could end up valued at 30-40% of the raw purchase value. If that's unintended, cap the compound adjustment by simplifying the rule set - keep the audience rule and drop the device/geo rules, or vice versa.

Order the rules by expected impact when documenting them internally - audience (biggest lever) first, then device, then geo. This helps forecasting when a rule is added or removed. At Visionary, we generally advise against more than 2 active rules per account to maintain "algorithmic transparency".

Smart bidding impact - how Google Ads uses rules

Only conversion-value-based smart bidding strategies use value rules: Target ROAS and Maximise Conversion Value (including tROAS variants in PMax). Target CPA and Maximise Conversions ignore value rules - they bid on conversion count, not value.

When you apply a rule, you are effectively "tilting" the auction house. Smart bidding doesn't know *why* you've made a mobile purchase worth less; it just knows it needs to find more "value" to hit its ROAS target.

What to Expect in the First 14 Days

Behavioural change after enabling NCAC on a Target ROAS campaign: bids on brand keywords and remarketing tend to compress (fewer repeat-customer conversions to chase); bids on new-user search and cold PMax audiences expand. Overall spend often stays flat while the mix shifts toward acquisition.

• CPC Volatility: You may see CPCs rise on non-brand terms as the algorithm "re-evaluates" their worth.
• ROAS Drop: Reported raw ROAS will likely dip. This is normal. You are paying for harder-to-get new customers.
• Conversion Volume: Might slightly decrease in the short term as the algorithm stops picking "low-hanging fruit" (repeats).

Do not simultaneously reduce Target ROAS to "compensate" for the rule - the rule already changes the ROAS calculation. Hold Target ROAS steady, let smart bidding find the new equilibrium, then adjust based on 3-4 weeks of results. If you change the target AND the rules at the same time, you'll never know which lever caused the resulting performance shift.

Reporting on rule-adjusted conversion values

Google Ads reports both raw and rule-adjusted values. It is easy to get these confused, which can lead to disastrous meetings with finance directors if you're reporting "inflated" rule values as actual revenue.

Reports columns: "Conv. value" shows raw; "Conv. value (adjusted)" or "All conv. value (rules)" shows rule-adjusted. Add both to campaign views.

Reporting rule: use raw values for external stakeholder reports (they need to reconcile to actual revenue). Use rule-adjusted values for internal bidding-decision analysis (understanding what smart bidding is chasing). Never mix - a report that switches between the two mid-way is unauditable. For more on how to bridge the gap between platforms, see our Performance Max eCommerce guide.

Common conversion value rules mistakes

In our audits of UK-based accounts, we see the same five errors repeatedly. Avoid these to ensure your value rules don't become a "value trap".

• 1. Guessing the multiplier instead of measuring LTV. Cohort-analyse 12-month spend by first-purchase source. If you think your LTV multiplier is 3x but it's actually 1.2x, you will aggressively over-bid on new customers and burn through your profit margin.
• 2. Stacking too many rules. Three or four compound rules produce extreme adjustments (e.g., valuing a conversion at 15% of its real worth) that confuse smart bidding and reporting. Two well-chosen rules (usually Audience + Geo) beats five noisy ones.
• 3. Chasing raw ROAS after enabling NCAC. The rule shifts spend to acquisition, which shows lower short-term ROAS but higher LTV-adjusted returns. If you panic and raise ROAS targets because "performance looks worse," you will kill the acquisition engine you just built. Measure over 12-week windows.
• 4. Applying rules to conversion actions not used by smart bidding. If your bidding strategy is set to "Purchase," creating a rule for "Newsletter signups" is a waste of time. Rules only impact bidding if the conversion action they apply to is part of the bidding optimization set.
• 5. Ignoring rules in Performance Max. PMax is an "all-in-one" beast. If you don't apply value rules, PMax will almost always take the path of least resistance: bidding on repeat customers via remarketing audiences. To make PMax a true growth engine, you *must* use NCAC value rules.

Frequently Asked Questions