Is Performance Max Stealing Credit for Sales It Didn’t Create?

Performance Max branded searches can make a Shopify campaign look more profitable than it really is.

A campaign showing a 400%, 500% or even 700% ROAS can look impressive.

But before increasing the budget, there is another question Shopify store owners should be asking:

Did Performance Max actually create those sales, or is Google Ads taking credit for customers who were likely to buy anyway?

That distinction is easy to miss.

Someone may already know your brand. They might have purchased from you before, seen you on Instagram, received one of your emails, clicked an organic Google result previously or visited your website directly.

Later, they search your business name on Google.

A Performance Max ad appears.

They click it and purchase.

Google Ads records a conversion.

Technically, the attribution may be correct. The customer clicked a Google ad before purchasing.

But that does not automatically mean Google Ads created the sale.

For Shopify businesses spending serious money on Google Ads, this matters.

A campaign can report strong conversion value and an attractive ROAS while generating less genuinely new business than the headline numbers suggest.

That does not mean Performance Max is bad.

It means you need to understand what sits underneath the ROAS before deciding whether the campaign deserves more money.

Can Performance Max take credit for sales you would have received anyway?

Yes.

Performance Max can generate and report conversions from both new and existing customers. It can also show ads when people search for your own brand unless you have campaign controls in place to prevent that. Google specifically provides brand exclusions for advertisers that want to control this behaviour.

That means some Performance Max conversions may come from shoppers who already know your business.

Those sales are still valuable.

What you need to separate is:

Attributed revenue: Revenue Google Ads reports as being associated with the campaign.

Incremental revenue: Additional revenue your business probably would not have generated without the advertising.

They are not always the same thing.

And if your objective is growth, incremental revenue is the number that really matters.

How Performance Max Branded Searches Can Inflate ROAS

Incremental revenue is revenue that happened because of your advertising rather than revenue that simply passed through your advertising.

Here is a simple example.

Imagine your Shopify store normally generates around $100,000 per month.

You then increase Google Ads spend from $10,000 to $20,000.

The following month Google Ads reports:

Google Ads spend: $20,000
Google Ads conversion value: $80,000
Reported ROAS: 400%

At first glance, that looks excellent.

But suppose total Shopify revenue increased from $100,000 to only $108,000.

You spent an additional $10,000 on Google Ads and Google reported $80,000 in attributed revenue, but the business only grew by $8,000.

That does not automatically prove Google Ads performed badly. There could be seasonality, changes in other advertising channels, stock issues, changes in conversion rate or plenty of other factors.

But it should make you investigate.

Where did that $80,000 of attributed Google Ads revenue come from?

How much was brand traffic?

How much came from repeat customers?

How much was genuine new customer acquisition?

Did Performance Max simply become better at taking credit for revenue that was already flowing through the business?

Those are much better questions than simply looking at the ROAS column.

Why PMax ROAS can look better than the real business result

ROAS is calculated using:

Conversion value ÷ advertising spend

Spend $10,000 and Google attributes $40,000 of conversion value to the campaign, and you have a reported ROAS of 400%.

There is nothing wrong with that calculation.

The problem is assuming that $40,000 represents $40,000 of additional revenue generated by Google.

It might.

But it might not.

Performance Max operates across multiple Google channels, including Search, YouTube, Display, Discover, Gmail, Maps and Search Partners. Google now provides channel performance reporting so advertisers can see how those different surfaces contribute to campaign performance.

A single PMax campaign can therefore contain a mixture of:

Branded Google searches.

Generic non-brand searches.

Google Shopping activity.

Remarketing.

YouTube advertising.

Display activity.

Gmail placements.

Discover traffic.

Existing customer activity.

New customer acquisition.

All of that can eventually roll up into one campaign ROAS figure.

So when somebody tells me:

“My Performance Max campaign is getting a 500% ROAS.”

My next question is:

Where is that 500% actually coming from?

Branded searches are one of the first things I check

A branded search contains the business name, website name, product brand or another term strongly associated with the business.

For example, imagine a hypothetical Shopify store called Harbour Living.

Brand searches might include:

Harbour Living

Harbour Living Sydney

Harbour Living cushions

Harbour Living table lamps

Harbour Living reviews

Harbour Living discount code

Someone typing those searches already knows the business exists.

Compare that with:

linen cushions Australia

ceramic table lamp

large decorative vase

black jewellery box

luxury throw blanket

Those shoppers are searching for products, not for a particular retailer.

Winning a sale from the second group is generally much stronger evidence that your Google Ads activity created or influenced new demand.

That is why brand traffic needs to be understood separately.

How branded searches can inflate the apparent strength of PMax

Imagine someone discovers your Shopify store through Instagram.

They browse some products but do not buy.

Three days later they decide they want the product after all.

Instead of typing your full website address, they Google your brand name.

A Performance Max Shopping or Search ad appears.

They click.

They purchase.

Google Ads records the conversion.

Performance Max now looks responsible for the sale.

But was it?

Instagram introduced the customer.

Your brand convinced them.

The customer had already decided to come back.

Google may simply have been the final route back to the website.

This is where attribution gets messy.

The Google conversion is real, but saying Google generated the customer is a much bigger claim.

Attribution and incrementality are not the same thing

This distinction is worth understanding because it applies well beyond Performance Max.

Attribution asks: Which marketing touchpoint should receive credit for the sale?

Incrementality asks: Would the sale still have happened without that marketing activity?

Those are completely different questions.

Google Ads can be involved in a conversion without necessarily being responsible for creating the underlying demand.

The same thing happens with other channels.

A customer might:

See an Instagram post.

Read a blog article.

Open an email.

Visit your website directly.

Leave.

Search your business on Google.

Click a PMax ad.

Purchase.

Multiple marketing activities helped.

Google Ads has strong visibility of the final part of the journey because the customer interacted with a Google ad.

That does not necessarily tell you which activity originally created the customer.

Does Performance Max advertise to existing customers?

Yes.

Performance Max is not automatically a new customer acquisition campaign.

By default, Google Ads can pursue sales from new and existing customers.

Google provides specific customer lifecycle settings for advertisers who want to change that behaviour. These include bidding more aggressively for new customers and a New Customer Only option for businesses with a strict customer acquisition objective.

This distinction becomes particularly important for established Shopify stores.

If you have been trading for several years and have:

20,000 previous customers

A large email database

Strong direct traffic

Good organic rankings

A recognisable brand

A large remarketing audience

then Google already has plenty of opportunities to generate conversions from people who know you.

That can produce very healthy ROAS numbers.

But it does not necessarily mean the campaign is bringing enough new customers into the business.

Existing customers are not bad customers

I want to be very clear about this.

Repeat customers are valuable.

Often they are your best customers.

They already know the business, understand the product and trust the store. They may have a higher conversion rate and lower acquisition cost than somebody buying for the first time.

The problem is not that Performance Max sells to existing customers.

The problem starts when a Shopify business thinks it is spending heavily on customer acquisition, while a large percentage of reported sales are actually coming from existing customers.

Those require different strategies and different expectations.

If the objective is retention, great.

If the objective is growth through new customers, you need to know how much genuine customer acquisition is occurring.

Google Ads has specific controls for new customer acquisition

Google’s customer lifecycle controls allow advertisers to change how campaigns treat new and existing customers.

For ecommerce advertisers, options include bidding higher for new customers, bidding more aggressively for high-value new customers and using New Customer Only mode where appropriate.

Google says the New Customer Value setting prioritises new customers while still allowing campaigns to engage existing customers. New Customer Only mode is more restrictive and is designed for advertisers with dedicated customer acquisition requirements.

For Shopify stores, customer lists and previous purchase data can help Google distinguish between customers it believes are new and those it believes have purchased before.

I would not switch these settings blindly.

They are tools.

You still need to understand your margins, repeat purchase behaviour, customer lifetime value and overall campaign strategy.

How can you tell if Performance Max relies heavily on your brand?

This has become much easier than it used to be.

Google now provides a Performance Max search terms report that can show the actual searches associated with PMax activity, along with landing pages and whether the relevant ad format was a Shopping ad or text ad.

That is one of the first places I look.

Go through the search terms producing conversions and ask:

How many contain the business name?

How many contain product brands you exclusively sell?

How many are navigational searches?

How many are genuinely generic product searches?

How many are high-intent commercial searches from people who may not know the business?

How many are poor or irrelevant searches?

This tells you far more than staring at the overall campaign ROAS.

Search Terms Insights are useful too

Individual search terms are valuable, but patterns matter as well.

If large groups of conversions sit around your business name, branded product combinations or other navigational terms, that can tell you the campaign is heavily involved in demand that already exists.

On the other hand, if profitable conversions are coming from generic searches such as:

best espresso machine for home

linen cushions Australia

UPS system for server room

outdoor furniture Sydney

organic oregano oil Australia

then Google is potentially introducing the business to shoppers with much broader commercial intent.

Neither category is automatically good or bad.

You simply need to know which one you are buying.

What are Performance Max brand exclusions?

Brand exclusions are a Google Ads control designed to prevent ads from serving for searches associated with specified brands.

For Performance Max, Google says brand exclusions can apply across Search and Shopping inventory.

One advantage of a brand list is that Google can recognise variations and misspellings of the brand rather than requiring you to manually build every possible negative keyword.

This makes brand exclusions useful when you want to keep your own branded searches out of a Performance Max campaign.

For example, you might run:

Campaign 1: Dedicated Brand Search campaign

Campaign 2: Performance Max with your own brand excluded

That gives you cleaner separation between customers deliberately searching for the business and people being reached through broader PMax activity.

Should every Shopify store exclude its brand from PMax?

No.

This is where Google Ads advice can become too simplistic.

You will sometimes hear:

“Always exclude your brand from Performance Max.”

I do not agree with blanket rules like that.

There are situations where branded advertising makes sense.

Competitors may be bidding on your brand.

Shopping results can give shoppers direct access to individual products.

You may want stronger control of the search results page.

Your branded traffic may be extremely profitable.

Customers searching your brand may still benefit from seeing relevant Shopping listings.

Google itself warns that brand settings can restrict traffic and potentially reduce conversion opportunities, which is why they should be used for campaigns where they suit the actual strategy.

The right question is not:

“Should every store exclude its brand?”

The right question is:

“What role do I want branded traffic to play in this particular campaign?”

When brand exclusions make more sense

I would look closely at a brand exclusion when:

You already have a dedicated branded Search campaign.

PMax is reporting a very strong ROAS but much of the converted traffic appears branded.

Your main goal is new customer acquisition.

You want a cleaner view of non-brand performance.

Your brand already has strong organic visibility.

You want to understand whether PMax can generate profitable demand without relying heavily on your business name.

You are trying to test incrementality.

This can produce a less flattering PMax ROAS.

That is not necessarily a bad outcome.

Sometimes less flattering data is more useful data.

When I would be cautious about excluding brand traffic

I would be more cautious when:

Competitors are aggressively bidding on your business name.

Your Shopping presence is strategically important for branded searches.

Brand traffic represents meaningful profitable revenue.

The business has weak organic visibility.

The account is very small and already has limited conversion data.

The exclusion would make it difficult for the campaign to generate enough volume to optimise effectively.

Again, context matters.

The objective is not to punish Performance Max.

The objective is to understand what it is doing.

Channel reporting has made PMax more transparent

One of the biggest historical complaints about Performance Max was the lack of visibility into where the budget was being used.

That has improved.

Google’s channel performance report provides channel-level information across Google Search, YouTube, Display, Discover, Gmail, Maps and Search Partners. Advertisers can also segment activity involving product data, which helps identify product-led advertising across Google’s inventory.

For Shopify advertisers, this is important.

Imagine your campaign has:

$10,000 total spend

$50,000 conversion value

500% overall ROAS

That still does not tell me enough.

I want to know what the campaign is actually doing.

Is most of the revenue coming through product advertising?

Is a large amount being spent on YouTube?

Is Display consuming budget without enough conversions?

Is Search producing most of the revenue?

Are branded searches doing the heavy lifting?

The overall campaign number can hide very different stories.

Why you should compare PMax with your Shopify revenue

Google Ads should never be reviewed completely in isolation.

Ultimately, Shopify tells you what happened to the store.

If Google Ads spend is climbing rapidly, I want to see what happens to:

Total Shopify revenue

Number of orders

First-time customers

Returning customers

Average order value

Conversion rate

Gross profit

Product mix

Overall advertising cost

Suppose Google Ads spend increases by 40%.

Google Ads conversion value increases by 45%.

That looks good.

But what if total Shopify revenue only increases by 5%?

I would want to know what is going on.

Maybe another channel declined.

Maybe the comparison period was unusually strong.

Maybe products went out of stock.

Maybe organic traffic dropped.

Maybe there is a tracking discrepancy.

Or maybe Google Ads is simply receiving more attribution for sales that were already occurring.

You cannot answer that question from Google Ads alone.

Compare Google Ads growth with actual business growth

I like looking at trends.

You do not need an overly complicated attribution model to notice something is not adding up.

If over three months:

Google Ads spend rises substantially.

Google Ads conversion value rises substantially.

Google Ads reports excellent ROAS.

But Shopify orders, revenue and new customer numbers barely change.

That deserves investigation.

On the other hand, if:

Google Ads spend rises.

Non-brand search activity increases.

New customer numbers rise.

Shopify revenue rises.

Order volume rises.

Profit remains healthy.

then you have much stronger evidence that the advertising is creating incremental business.

That is the type of growth I want to scale.

Revenue is not enough either

There is another layer Shopify stores often ignore.

Profit.

A PMax campaign could produce $50,000 in reported sales and still be poor commercially.

Products have different margins.

A $300 item with a 20% gross margin is very different from a $300 item with a 60% gross margin.

Then you have:

GST

Shipping

Merchant fees

Discounting

Returns

Cost of goods

Agency or management costs

Other operating expenses

This is why I like knowing the store’s approximate break-even ROAS.

If a business needs a 300% ROAS just to break even, a campaign running at 320% is not necessarily something I would aggressively scale.

A reported ROAS that contains lots of branded sales makes that decision even more important.

Product-level performance matters

Performance Max can also look healthy because a small number of products are doing most of the work.

For example:

Ten products are profitable.

Forty products are average.

One hundred products spend money and rarely convert.

The campaign-level ROAS may still look acceptable because the winners are covering the losers.

That is another reason I do not like judging ecommerce campaigns from the top-level number.

Look at individual products and categories.

Which products are producing revenue?

Which products are spending without converting?

Which have enough margin to support paid acquisition?

Which products sell strongly through organic or direct traffic anyway?

Which products attract new customers?

Which products lead to repeat purchases?

A PMax campaign should not receive unlimited freedom just because the blended number looks reasonable.

Do not confuse remarketing with customer acquisition

Performance Max can interact with shoppers at different stages of the buying process.

Some people are discovering your products for the first time.

Others may have visited several times already.

Some may have purchased from you before.

The closer a customer already is to purchasing, the easier it can be for advertising to receive credit.

That is why warm audiences often convert well.

But a high conversion rate from warm traffic does not automatically prove strong customer acquisition.

If your business needs growth, you need both:

Demand capture: Converting people already interested in your business or products.

Demand generation and acquisition: Finding additional customers who would not otherwise have purchased.

A healthy Google Ads strategy should understand the difference.

What I check when a PMax campaign looks almost too good

If I inherit a Shopify Google Ads account showing an unusually strong Performance Max ROAS, I do not immediately celebrate.

I start checking.

1. Conversion tracking

Is Purchase the correct primary conversion?

Is revenue passing accurately?

Are duplicate purchase conversions being counted?

Are other actions accidentally being included in the main conversion column?

Poor tracking can make every other analysis meaningless.

2. Search terms

What searches are actually triggering the ads?

How much is branded?

How much is generic?

Which searches generate the conversions?

Google’s PMax search terms reporting now gives advertisers substantially more visibility into these queries.

3. Brand exposure

Is Performance Max advertising against the business’s own brand?

Does a separate brand campaign already exist?

Would brand exclusions provide a cleaner structure?

4. New customers

Are new customer numbers actually increasing?

Or are most conversions coming from people who have purchased before?

5. Channel activity

Where is PMax actually delivering ads?

Search?

YouTube?

Display?

Discover?

Gmail?

Maps?

Search Partners?

Use Google’s channel performance reporting rather than assuming PMax is mainly Shopping.

6. Product performance

Which SKUs and categories produce profitable revenue?

Which are spending without enough return?

7. Shopify performance

Did Shopify revenue rise?

Did order numbers rise?

Did the number of new customers rise?

8. Profitability

Is the campaign above the actual break-even ROAS?

9. Spend versus incremental growth

When advertising spend increased previously, did business revenue increase with it?

This last question is one of the most important.

A simple example

Imagine two Shopify stores.

Both spend:

$10,000 on Performance Max

Both report:

$50,000 conversion value

Both therefore show:

500% ROAS

On the Google Ads dashboard, they look identical.

But Store A receives most of its conversions from previous customers and branded searches.

Its Shopify revenue was already around $200,000 per month and remains around $202,000.

Store B receives much more of its revenue from generic commercial searches and new customers.

Its Shopify revenue rises from $100,000 to $135,000.

Same Google Ads ROAS.

Completely different business result.

Which campaign would you feel more confident scaling?

That is why attribution matters.

What should a Shopify business look at before increasing its PMax budget?

Before increasing spend, I would want answers to these questions:

How much of the conversion value is brand related?

Are conversions coming from new or existing customers?

Which products are generating the revenue?

Which products are wasting spend?

Which Google channels are consuming the budget?

Is Shopping activity profitable?

Are search terms commercially relevant?

Has total Shopify revenue increased?

Have total Shopify orders increased?

Are new customer numbers increasing?

Is the campaign comfortably above break-even ROAS?

What happened the last time the budget increased?

If you cannot answer those questions, increasing the budget simply because the dashboard says 500% ROAS is risky.

Does this mean Performance Max cannot drive incremental sales?

Absolutely not.

Performance Max can be a very effective ecommerce campaign type.

For the right Shopify store, with good conversion tracking, strong product data, sensible campaign structure and enough sales history, it can produce excellent results.

The point is not that PMax is somehow cheating.

The point is that attribution needs interpretation.

Google Ads is designed to optimise towards the conversion goals and data you give it.

If the easiest profitable conversion happens to be someone who already knows your business, the system has a strong incentive to pursue that opportunity unless your settings and strategy tell it otherwise.

That may be exactly what you want.

Or it may not.

Your campaign structure should reflect the business objective.

Performance Max should help the business grow, not just the Google Ads dashboard

This is where I think ecommerce advertisers sometimes lose perspective.

A Google Ads account can look fantastic while the business owner is sitting there wondering:

“Why don’t I feel like sales have improved?”

That is a warning sign.

The Google Ads interface is not the business.

Shopify is closer to the business.

Your bank account is closer again.

If advertising spend keeps increasing, I want to see additional profitable revenue appearing somewhere.

Not just additional attributed revenue inside Google Ads.

That does not require perfect attribution.

Perfect attribution probably does not exist.

It requires sensible commercial analysis.

The real question is not whether Google gets credit

Google Ads needs an attribution system.

Without attribution, you cannot optimise campaigns.

The issue is how you interpret that attribution.

If Google reports $100,000 in sales, do not automatically assume:

“Google created $100,000 in business.”

Instead ask:

“What would probably have happened without this advertising?”

You may never get a perfectly precise answer.

But looking at brand traffic, new customers, Shopify revenue, product performance, channel activity and changes in spend gets you much closer.

And that gives you a much better basis for deciding whether to scale.