1. Why New Customer Optimization Matters

Without a dedicated new customer optimization strategy, Google's algorithm rewards every purchase equally, regardless of whether it comes from a new or existing customer.

As a result, a significant portion of your advertising budget is often spent on existing customers. Since these customers are already familiar with your brand, they typically convert more easily, making them an attractive target for Google's optimization algorithms.

However, these customers could often have been reactivated much more cost-effectively through owned channels such as email, WhatsApp, or SMS, rather than spending additional advertising budget to acquire purchases that may have happened anyway.

By using Mable's NewCustomerPurchase conversion as the campaign's optimization goal instead of the standard Purchase conversion, Google is rewarded only when a new customer completes a purchase.

Over time, the algorithm learns to prioritize users who are more likely to become new customers. This allows you to acquire more new customers with the same advertising budget, reduce customer acquisition costs (CAC), and scale campaigns more efficiently.

The conversion goal has an especially strong impact on highly automated campaign types such as Performance Max and Demand Gen.

We therefore recommend:

• Optimize PMAX and Demand Gen campaigns for NewCustomerPurchase.

• Generic Search and Shopping campaigns can also benefit from optimizing for NewCustomerPurchase.

• Brand Search and Brand Shopping campaigns should typically continue optimizing for the standard Purchase conversion, since their purpose is often to capture both new and returning customers.

2. Prerequisites for New Customer Optimization

2.1 Review Your Google Ads Setup

Before optimizing campaigns for new customer acquisition, make sure your Google Ads account follows the recommended setup.

In particular:

• Purchase should be the only Account Default Goal.

• Other goal categories, such as AddToCart, should not be enabled as Account Default Goals.

• Each goal category should have only one Mable conversion action per store configured as Primary.

For the complete setup guide, see ⬇:

Google Ads Best Practice Setup

2.2 Create Custom Goals for New Customer Optimization

We recommend using Custom Goals for new customer optimization.

A Custom Goal allows you to create a dedicated conversion goal for each relevant conversion action.

This lets you decide on a campaign-by-campaign basis whether Google should optimize for:

• Standard Purchase conversions, or

• NewCustomerPurchase conversions.

This approach also allows your existing campaigns—including brand campaigns—to continue optimizing for standard purchases while selected campaigns are gradually transitioned to new customer optimization.

You can create Custom Goals under:

Goals → Summary → Scroll to the bottom → Custom Goals

If your account contains only a single Mable NewCustomerPurchase conversion action, your New Customer Purchase Custom Goal should include only that conversion.

If your account contains multiple NewCustomerPurchase conversion actions for different markets, you can either:

• Create separate market-specific New Customer Purchase Custom Goals, or

• Create one global Custom Goal containing all NewCustomerPurchase conversion actions.

For step-by-step instructions, see:

How to Create NewCustomerPurchase Custom Goals in Google Ads

3. Optimize Campaigns for New Customers

After creating the NewCustomerPurchase Custom Goal, allow it to collect sufficient conversion data before using it for optimization.

⚠ Important:
Before switching your first campaign to the NewCustomerPurchase Custom Goal, allow Google to build an initial data set.

We recommend waiting at least seven days after the event is first sent to Google Ads.

Ideally, this waiting period should match the click attribution window configured for the NewCustomerPurchase conversion (often 30 days). In practice, however, this is usually unnecessary, and seven days is sufficient for most accounts.

If Mable has already been connected for more than seven days and the event has been sent continuously since then, you can proceed immediately.

Once enough data has been collected, you can begin optimizing campaigns for NewCustomerPurchase instead of the standard Purchase conversion.

To do so:

1. Open your campaign settings.

2. Under Campaign Conversion Goal, select Campaign-specific goal (instead of Account Default Goals).

3. Select your previously created NewCustomerPurchase (Custom) goal.

Only that campaign will optimize for new customers. All other campaigns remain unchanged.

For detailed instructions, see:

How to Switch a Google Ads Campaign to New Customer Optimization

4. Review Target ROAS and Target CPA for New Customer Campaigns

If your campaigns currently use Target ROAS or Target CPA, you should review these bidding targets before switching to NewCustomerPurchase optimization.

The reason is simple:

Once the campaign optimizes exclusively for new customer purchases, significantly fewer conversions are available for Google's optimization algorithm.

As a result, your previous bidding targets may become much harder to achieve.

Example

Before the switch

• Optimization based on all purchases

• Target ROAS = 300%

• New customer rate = 67%

Before the switch:

• Target ROAS measures return across all purchases

• Target CPA represents your cost per order

After switching to NewCustomerPurchase, only purchases from new customers count as conversions.

This changes the meaning of your bidding targets:

• Target ROAS → Target New Customer ROAS

• Target CPA → Target CAC (Cost per New Customer)

A previous Target ROAS of 300% therefore no longer represents the same optimization objective and may be significantly more difficult for Google to achieve.

Potential Impact

If your existing bidding targets remain unchanged, Google may limit campaign delivery more aggressively than intended.

Common symptoms include:

• Lower spend

• Fewer impressions

• Fewer clicks

• Lower conversion volume

Recommended Approaches

We generally recommend one of two approaches.

Option 1: Adjust Your Existing Target

Adjust your existing Target ROAS based on your historical new customer rate.

Example

• Target ROAS = 300%

• New customer rate = 67%

Estimated Target New Customer ROAS = approximately 200%

Option 2: Temporarily Remove the Target

Alternatively, switch your bidding strategy to:

• Maximize Conversion Value, or

• Maximize Conversions

without setting a bidding target.

This gives Google's algorithm time to learn the new optimization signal.

After several weeks, observe where the campaign naturally stabilizes and use that performance to define a new Target New Customer ROAS.

Regardless of which approach you choose, you should always verify:

• Whether your existing Target ROAS remains appropriate

• Whether your existing Target CPA still reflects your business goals

• Whether the campaign is receiving enough conversion volume for effective optimization

If campaign delivery drops significantly after the switch, it is often helpful to temporarily relax your bidding targets and gradually tighten them again after several weeks, once Google's algorithm has adapted to the new optimization objective.

5. Best Practices for Switching to New Customer Optimization

When getting started with NewCustomerPurchase optimization, we recommend taking a gradual approach.

During the initial learning phase, campaign performance may temporarily decline while Google's algorithm adapts to the new optimization signal. At the same time, the algorithm still needs enough conversion data to learn effectively.

As a starting point, we recommend allocating approximately 15–30% of your non-brand advertising budget to campaigns optimizing for NewCustomerPurchase.

After a few weeks, review the results.

If your key new customer metrics improve, gradually shift more budget to these campaigns.

A typical rollout looks like this:

• Duplicate your existing campaigns.

• Configure the duplicated campaigns to optimize for NewCustomerPurchase.

• Start with only a few campaigns or a reduced budget.

This keeps your existing campaigns stable while allowing the new campaigns to learn in a controlled environment.

If the following metrics improve over time:

• New customer rate

• Customer Acquisition Cost (CAC)

• New Customer ROAS (NC ROAS)

you can gradually increase the budget for your NewCustomerPurchase campaigns while reducing spend on your existing Purchase campaigns until all non-brand campaigns optimize exclusively for NewCustomerPurchase.

While it's also possible to update existing campaigns directly, this approach typically results in greater short-term performance fluctuations.

6. Learning Phase & Expectations

When campaigns optimize for NewCustomerPurchase for the first time, Google's algorithm must learn an entirely new optimization pattern.

As a result, campaigns typically enter a significant learning phase.

During the first two to three weeks, performance may temporarily appear weaker than before.

This is completely normal.

Patience is essential during this period.

Once Google's algorithm has learned the new optimization signal, it gradually shifts budget away from existing customers and toward acquiring new ones.

Because the algorithm can no longer rely on easily converting returning customers, you may see:

• A higher cost per order

• A lower overall ROAS

At the same time, your new customer metrics should improve.

Typically:

• Customer Acquisition Cost (CAC) decreases.

• New Customer ROAS (NC ROAS) increases.

For this reason, switching to NewCustomerPurchase optimization only makes sense if acquiring new customers is your primary business objective.

Campaign performance should therefore be evaluated using new customer KPIs rather than traditional purchase metrics.

The most important KPIs become:

• New customer purchases

• Customer Acquisition Cost (CAC)

• New Customer ROAS (NC ROAS)

• New customer rate

7. Understanding KPI Changes After the Switch

It's also important to understand that some standard Google Ads metrics change their meaning after switching to NewCustomerPurchase optimization.

If a campaign previously optimized for the standard Purchase conversion and is then switched to NewCustomerPurchase, you'll typically notice:

• Fewer Conversions

• A higher Cost per Conversion

This does not mean campaign performance has declined.

Instead, Google is simply reporting a different KPI.

Before the switch:

• Conversions represents the total number of orders.

• Cost per Conversion represents your Cost per Order (CPO).

After switching to NewCustomerPurchase:

• Conversions represents the number of new customers acquired.

• Cost per Conversion effectively becomes your Customer Acquisition Cost (CAC).

For example, if your historical new customer rate was 50%, switching to NewCustomerPurchase will naturally result in approximately:

• Half as many reported conversions

• Roughly double the Cost per Conversion

This is expected because:

• Previously, Google reported Cost per Order.

• After the switch, it effectively reports Customer Acquisition Cost.

For a detailed explanation of how KPIs such as Conversions and Cost per Conversion change after switching to new customer optimization—and how to evaluate campaign performance correctly—see ⬇:

Google Ads Reporting & KPI Analysis for New Customer Optimization

8. Customer Lifecycle Goals vs. True New Customer Optimization

Google Ads offers its own feature called Customer Lifecycle Goals for new customer acquisition.

However, this functionality relies entirely on Customer Match lists.

To use it, you must upload a list of your existing customer email addresses.

Google then attempts to match those email addresses with Google users in order to identify existing customers. Future purchases are classified as either new or returning customers based on that matched audience.

In practice, this approach is often unreliable because Customer Match lists typically have incomplete match rates.

As a result, Google may incorrectly classify some returning customers as new customers, leading to an inflated new customer rate.

For this reason, we do not recommend relying exclusively on Customer Lifecycle Goals for new customer optimization.

Instead, the key optimization signal should be the Mable NewCustomerPurchase conversion, which campaigns can directly optimize toward.

Customer Lifecycle Goals and audience targeting can still be valuable complementary tools.

However, in practice, we've consistently observed significantly stronger results when campaigns optimize directly for a true NewCustomerPurchase conversion.

The reason is simple.

Customer Lifecycle Goals primarily influence audience selection.

If your campaign continues optimizing for the standard Purchase conversion, Google's algorithm is still rewarded for every purchase, regardless of whether it comes from a new or returning customer.

This means Customer Lifecycle Goals and the campaign's optimization objective can work against each other.

Customer Lifecycle Goals encourage Google to prioritize new customers, while the Purchase conversion continues rewarding all purchases equally.

Optimizing directly for NewCustomerPurchase changes the algorithm's actual learning signal.

As a result, the campaign objective and the new customer strategy are fully aligned, reinforcing one another and producing significantly stronger optimization outcomes.