Google Ads has dozens of metrics. Most reports show ten or fifteen by default. If you have a manager sending you monthly summaries, you probably see impressions, clicks, click-through rate, conversions, ROAS, cost per conversion, spend, and a few others depending on how the report is set up.
Most of these numbers are noise for a business owner trying to answer the only question that actually matters: is this money working?
This post tells you the three numbers that give a genuine answer to that question, and which common metrics tend to mislead more than they help.
The Three Numbers Worth Watching
1. Cost per new customer acquisition
This is the amount you are paying in ad spend to bring in a customer who has not purchased from you before. It is distinct from cost per conversion, which includes repeat purchases by existing customers.
Why it matters: growing a store requires acquiring new customers. Retaining existing customers has real value too, but if Google Ads is primarily selling to people who already know your brand, it is doing expensive retention work rather than growth. The cost of acquiring a genuinely new customer tells you how efficiently the channel is building your customer base.
How to get a rough version of this number: compare Google Ads conversion volume to your new customer rate in Shopify for the same period. Shopify can show what percentage of orders came from first-time customers. If Google Ads is producing 50 conversions per month and 60 percent of those are existing customers based on Shopify’s data, the effective new customer count from the ads is closer to 20. Divide the ad spend by 20, not 50, to get the real acquisition cost.
A more precise version requires proper tracking setup, including audience segmentation that separates new and returning converters in the Google Ads conversion data. But the rough version is enough to reveal whether the gap between reported and real acquisition cost is significant.
2. Account-level ROAS adjusted for brand
The account-level ROAS you see in the dashboard is a blended number that includes branded traffic (people searching for your store name), retargeting conversions (existing visitors and customers), and non-branded new traffic. These segments have very different economics.
A meaningful ROAS number strips out branded conversions and looks at what you are generating from non-branded, prospecting traffic. This is the ROAS that tells you whether the ads are worth running at the current spend level.
For most stores, the adjusted non-branded ROAS is noticeably lower than the blended ROAS. A store reporting 4x overall might be 2.5x on non-branded alone. Whether 2.5x is good depends on margins, but it is the honest number for evaluating whether the channel justifies its spend on new customer acquisition.
If your account does not separate branded and non-branded campaigns, this number is not easily visible. Getting it requires either restructuring the account or doing manual analysis of the conversion data by query type.
3. Conversion tracking confidence
This is not a metric in the traditional sense. It is an ongoing assessment of whether the numbers you are looking at are accurate.
A store that knows its conversion tracking is working correctly and producing accurate revenue values can make confident decisions based on the data. A store that is unsure about its tracking is making decisions based on a number that may be 20 percent too high, or 30 percent too low, or anything in between.
The practical check: does the conversion volume in Google Ads track proportionally with your actual Shopify order volume? Do the revenue values in Google Ads approximately match your actual revenue from Google traffic? Is there any month where the two diverge significantly, suggesting a tracking break?
Once you have confidence in the tracking, the other two numbers above are interpretable. Without it, they are guesses dressed up as data.
The Numbers That Mislead Most Owners
Impressions and click-through rate. These measure how your ads perform in the auction: how often they are shown and how often people click. They are useful for diagnosing specific technical problems (very low CTR on a Shopping campaign might indicate poor product images or prices). But they say nothing about whether the ad spend is returning value to the business. A campaign can have excellent CTR and terrible ROAS. It can have low CTR and great conversion rates.
Overall conversion count without context. If conversions are up month over month, that sounds good. But if the increase is entirely from branded search traffic because you ran a large promotion that brought existing customers back, the conversion count increase tells you nothing about whether the underlying acquisition machine is working better.
Quality score. Quality score is a Google-specific metric that measures ad relevance, expected CTR, and landing page experience. It is useful for diagnosing why your cost per click is higher than competitors in the same auction. But chasing quality score improvements as a primary goal is a distraction. Many high-spending, profitable accounts have mediocre quality scores. Many accounts with perfect quality scores are not profitable.
Cost per click in isolation. A rising cost per click is worth investigating, but it is not inherently a problem. If cost per click rises 20 percent but conversion rate rises 25 percent (because you improved targeting or landing pages), the effective cost per conversion is lower. CPC by itself, without conversion rate context, is half a picture.
ROAS without margin context. As discussed elsewhere in this series, a ROAS number without knowing your gross margins is incomplete. A 3x ROAS is great for a 70 percent margin product. It is a loss-maker for a 25 percent margin product. When your manager reports ROAS, the meaningful comparison is against your break-even ROAS given your margins, not against a generic “good ROAS” benchmark.
Building a Dashboard That Actually Answers the Question
If you have access to your Google Ads account and want to track the numbers that matter, the simplest version looks like this:
Weekly: check spend, conversion count, and conversion value. Make sure these are moving in a direction consistent with actual order volume in Shopify.
Monthly: look at blended ROAS and non-branded ROAS (if your account separates them). Compare to the same month last year to account for seasonality.
Quarterly: assess new customer acquisition cost compared to what a new customer is worth to your business over time. This is the number that tells you whether Google Ads is growing the business.
Getting This Fixed
Getting the right metrics visible, and understanding what they actually mean for your business, is part of the setup and ongoing review work I do with ecommerce stores. Most stores are either watching the wrong numbers, watching the right numbers but without enough context to interpret them, or both.
If you want to build a cleaner view of what your ads are actually doing, reach out at adnanagic.com/#contact.
Part of the Google Ads for Store Owners series, written for ecommerce owners who want their ad spend to actually work.
Related Posts
- Your Google Ads ROAS Looks Great but Your Bank Account Disagrees: Why
- Profit Margin and POAS: The Better Way to Measure Google Ads Ecommerce Performance
- The Real Cost of Bad Conversion Tracking
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