1. Why Your Google Ads Setup Matters

By default, Google Ads optimizes campaigns based on conversion actions that are both:

• Set to Primary

• Included in either the account's default goals or the campaign's custom conversion goal

Google's algorithm relies heavily on these configured conversion goals to identify users who are most likely to complete the desired actions.

If your setup isn't configured correctly, Google may receive conflicting optimization signals. For example, it could optimize simultaneously for Purchases and Add to Cart events, even though only purchases are relevant to your business.

This often results in:

• Inefficient budget allocation

• Lower-quality revenue

• Misleading KPIs

Before optimizing campaigns—whether for Purchases, New Customers, or Profit—you should first verify that your Google Ads account is configured according to best practices.

2. Configure Primary Conversions Correctly

2.1 Set Only the Relevant Purchase Conversion to Primary

As a general best practice, we recommend setting only the Mable Purchase Conversion Action to Primary for each store or market.

Additional purchase-derived conversion actions such as:

• NewCustomerPurchase

• ReturningCustomerPurchase

• CM1 AllCustomerPurchase

should all be configured as Secondary.

Likewise, any previously used purchase conversion actions for the same store—such as those created by the Shopify App, the Google & YouTube App, or other tracking solutions—should also be changed to Secondary.

Ideally, make this change after approximately 30 days, or sooner once the Mable Purchase Conversion Action has collected sufficient data and is reliably recording conversions.

Google uses Primary conversions for Smart Bidding and campaign optimization.

If multiple purchase conversion actions for the same store are set to Primary, Google receives duplicate or conflicting optimization signals. This can lead to:

• Poorer algorithm performance

• Inflated conversion counts

• Overstated conversion values

You can review these settings under:

Goals → Summary → Conversions → Select the Conversion → Action Optimization

For detailed instructions, see ⬇:

How to Change Conversion Goal Action Optimization in Google Ads

2.2 Special Considerations for Existing Target ROAS Campaigns

If your account previously had multiple purchase conversion actions for the same store configured as Primary, and your campaigns use Target ROAS, there is one additional consideration before cleaning up your setup.

In many cases, multiple purchase conversion actions record the same purchases.

If all of these conversion actions are configured as Primary, Google attributes the same order multiple times.

As a result:

• Google reports more conversions than actually occurred.

• Conversion values become artificially inflated.

• Smart Bidding and Target ROAS are trained on incorrect data.

After cleaning up your setup and leaving only a single Purchase conversion set to Primary, Google suddenly sees fewer conversions and lower conversion values.

Although this is the correct configuration, an existing Target ROAS based on the inflated historical data may suddenly become impossible to achieve.

As a result, Google may significantly reduce:

• Spend

• Impressions

• Traffic

⚠ Important:
The solution is not to restore multiple Purchase conversions as Primary.

Cleaning up your conversion setup is still the correct approach.

Instead, review your bidding strategy and adjust it to reflect the new conversion logic.

Recommended Approaches

If you're switching from multiple Purchase conversions to a single Mable Purchase conversion, we recommend one of the following approaches.

Option 1: Adjust Your Target ROAS

If you can estimate how much your attributed conversion value decreases after the cleanup, reduce your Target ROAS accordingly.

Navigate to:

Goals → Summary → Purchase

Review the attributed conversion values for your existing Purchase conversion actions.

Example

Before cleanup

• Google Shopping App Purchase: €12,307

• Mable Purchase: €16,091

After cleanup

Only Mable Purchase remains as Primary.

Calculation:

16,091 ÷ (12,307 + 16,091) = 56.7%

Your new Target ROAS should therefore initially be approximately 56.7% of your previous target.

Example:

• Previous Target ROAS: 275%

• New Target ROAS: approximately 156%

Option 2: Temporarily Remove the Target

If the impact of the cleanup cannot be estimated reliably—or if Google significantly reduces spend even after adjusting your Target ROAS—you can temporarily switch to either:

• Maximize Conversion Value

• Maximize Conversions

without setting a target.

Once campaign performance has stabilized using the cleaned-up conversion data, you can define a new Target ROAS.

Depending on the account, it's often beneficial to allow this transition period to run for two to four weeks before reintroducing a Target ROAS.

3. Configure Account Default Goals Correctly

The most important part of your Google Ads setup is configuring your Account Default Goals.

Campaigns using Account Default Goals automatically optimize toward every active goal category.

For example, if both Purchase and Add to Cart are enabled as account default goals, Google will optimize for both actions simultaneously.

The problem is that Add to Cart is much easier to achieve than an actual purchase.

As a result, Google's optimization often shifts toward cheaper—but lower-quality—signals, which can lead to:

• Lower-quality revenue

• Distorted KPIs

• Inefficient budget allocation

Additionally, Google combines multiple conversion types into the same reporting metrics, which often causes:

• Artificially inflated Conversions

• Artificially inflated Conversion Value

• Misleadingly low Cost per Conversion

We therefore recommend:

• Enable Purchase as the only Account Default Goal.

• Set all other goal categories to Don't use.

⚠ Important:
Adjusting your Target ROAS or Target CPA is not required every time you change your Account Default Goals.

However, you should review your bidding targets if:

- Multiple goal categories were previously enabled as Account Default Goals.

- Those goal categories include Primary conversions with historical data.

- Active campaigns are optimizing using Account Default Goals.

- Those campaigns use Target ROAS or Target CPA.

In these situations, cleaning up your Account Default Goals can significantly reduce both the number of attributed conversions and the reported conversion value.

Existing Target ROAS or Target CPA settings may therefore become overly restrictive and limit campaign delivery.

To adjust your bidding targets, follow the same approach described in Section 2.2.

You can review these settings under:

Goals → Select the Goal Category → Edit Goal

For detailed instructions, see ⬇:

How to Configure Account Default Goals in Google Ads

4. Why "Primary" and "Account Default Goal" Are Not the Same

It's important to understand that Primary and Account Default Goal are two different settings.

A conversion action can remain Primary without Google automatically optimizing toward it.

Whether Google actually uses a conversion for optimization depends on whether:

• Its Goal Category is enabled as an Account Default Goal, or

• It is included in a campaign-specific conversion goal.

This distinction is especially important for upper-funnel events such as AddToCart or BeginCheckout.

If a goal category no longer contains any conversion action marked as Primary, Google often stops attributing and reporting that goal category correctly.

We therefore recommend:

• Keep one conversion action per goal category set to Primary.

• Use the corresponding Mable conversion action whenever possible.

• Do not enable that goal category as an Account Default Goal.

For example, if you want to analyze AddToCart conversions later using All Conversions or by segmenting reports by Conversion Action, you should leave exactly one Primary conversion action for the AddToCart goal category—ideally the corresponding Mable conversion.

The key is simply not to enable that goal category as an Account Default Goal.

This preserves attribution and reporting while preventing Google from actively optimizing toward these upper-funnel events.

5. Best Practice Summary

Conversion Actions

• Set only the Mable Purchase Conversion Action to Primary for each store or market.

• Set NewCustomerPurchase, ReturningCustomerPurchase, CM1 AllCustomerPurchase, and other purchase-derived conversion actions to Secondary.

• Change any previously used Purchase conversion actions for the same store to Secondary.

• Only use multiple Primary Purchase conversions when they belong to different stores or markets.

Account Default Goals

• Enable Purchase as the only Account Default Goal.

• Set all other goal categories to Don't use.

• If your account uses Target ROAS or Target CPA, review whether cleaning up your Account Default Goals changes the underlying conversion logic.

Funnel Events

• Keep exactly one Mable conversion action per goal category set to Primary.

• Do not enable that goal category as an Account Default Goal.

• This preserves attribution and reporting without causing Google to optimize toward those events.

Target ROAS / Target CPA

• When cleaning up multiple Primary Purchase conversions, review any existing Target ROAS settings.

• If possible, estimate the change in attributed conversion value and adjust your Target ROAS accordingly.

• Alternatively, temporarily switch to Maximize Conversion Value or Maximize Conversions without a target.

• Once the account has stabilized, define a new Target ROAS or Target CPA.

6. Next Steps

Once your Google Ads account is configured according to these best practices, you can begin optimizing campaigns for specific business objectives.

New Customer Optimization

For the complete guide, see ⬇:

New Customer Optimization in Google Ads

Profit Optimization

For the complete guide, see ⬇:

Profit Optimization in Google Ads

Reporting & KPI Analysis

Before switching your optimization strategy, we also recommend reviewing how reporting and KPI interpretation change.

For detailed guidance, see ⬇:

• Google Ads Reporting & KPI Analysis for New Customer Optimization

• Profit Reporting in Google Ads