News & Insights
The Ecommerce PPC Metrics That Actually Drive Results
Ask ten PPC managers which metrics they’re watching, and you’ll likely get ten different answers. Click-through rates. Cost-per-click. Impression share. The list goes on. The problem isn’t a shortage of data – it’s knowing which PPC metrics genuinely matter for your ecommerce business, and which ones are just noise.
At Circus PPC, we work with ecommerce businesses every day, and one of the most common things we see is budgets being managed against the wrong metrics. It leads to decisions that look good on paper, but don’t translate into actual growth.
So, which ecommerce PPC metrics are actually going to make a difference to your performance? We’ve broken them into three groups: the classics you should absolutely be tracking, some less obvious ones worth adding to your dashboard, and the ones that tend to distract more than they inform.
3 Classic Ecommerce PPC Metrics That Matter
These are the fundamentals – the metrics every ecommerce business should have front and centre when evaluating PPC performance.
Revenue
It sounds obvious, but you’d be surprised how often revenue gets buried beneath layers of intermediary metrics. At the end of the day, PPC exists to drive sales. Revenue – the actual money coming through the door from your paid campaigns – is a clear measure of whether that’s happening.
Where businesses go wrong is optimising towards proxy metrics (impressions, clicks, even conversions) without tying them back to revenue. A campaign can rack up hundreds of conversions and still be losing you money if those conversions are low-value or poorly attributed.
ROI (Return on Investment)
ROI gives you the big-picture view of how much you’re getting back for every pound you put in. For ecommerce, this typically means looking at revenue generated against total ad spend – though the most accurate version factors in product costs and overheads too.
A healthy ROI target varies significantly by sector, margin profile, and business stage. A brand in aggressive growth mode might accept a lower short-term ROI in exchange for customer acquisition. An established retailer with tight margins might need that number carefully managed.
POAS (Profit on Ad Spend)
ROAS (Return on Ad Spend) gets a lot of airtime, but POAS is another metric we’d encourage more ecommerce businesses to get familiar with. Where ROAS measures revenue relative to ad spend, POAS measures profit – a crucial distinction when your products carry very different margins.
Imagine you’re running ads for two product lines. Line A has a ROAS of 8x but a margin of 10%. Line B has a ROAS of 4x but a margin of 45%. Optimising purely for ROAS pushes budget towards Line A – even though Line B is far more profitable. POAS takes this into account and sees more than ROAS might.
3 Helpful Ecommerce PPC Metrics You Might Not Be Aware Of
These metrics don’t always make it onto the standard dashboard, but they offer a level of insight that can genuinely change how you manage campaigns.
Search Lost IS (Impression Share Lost to Budget/Rank)
Impression Share (IS) tells you what percentage of available impressions your ads are actually showing for. Search Lost IS breaks that down further, showing you how much potential visibility you’re missing – and crucially, whether it’s because of budget constraints or ad rank issues.
This matters because the fix is very different depending on the cause. Lost IS due to budget means you’re simply running out of money before all eligible searches are covered. Lost IS due to rank means your bids or Quality Scores aren’t competitive enough, and throwing more budget at the problem won’t solve it.
Thumbstop Rate
Thumbstop rate is a metric more commonly associated with paid social – particularly Meta and TikTok – and it measures the percentage of people who stop scrolling to watch or engage with your ad. In a feed dominated by content, it’s one of the clearest signals of whether your creative is actually cutting through.
For ecommerce brands investing in social ads, a low thumbstop rate is often the root cause of poor downstream performance. Your targeting might be fine, your offer might be strong, but if the creative doesn’t make someone pause, none of that matters.
Profit vs Loss by Product
This is less a single metric and more a lens through which to view your campaign performance. Breaking down profitability at the product or SKU level – accounting for ad spend, cost of goods, returns, and fulfilment – reveals which products your PPC activity is actually making money on, and which are quietly draining budget.
Many ecommerce businesses are surprised to find that a significant portion of their PPC spend is going towards products that, after all costs are considered, generate little or no profit. In some cases, heavily advertised products could be actively loss-making.
3 Ecommerce PPC Metrics To Avoid Getting Hung Up On
These metrics aren’t useless – but they’re frequently misread, over-weighted, or used as a basis for decisions they shouldn’t be driving.
CPC (Cost Per Click)
Cost per click is one of the most watched metrics in PPC, and also one of the most misunderstood. A low CPC feels like a win. A high CPC triggers concern. But without context, CPC tells you almost nothing about the quality of your results.
A £0.30 click that never converts is far more expensive than a £3.00 click that reliably generates a £150 sale. The obsession with driving CPC down often leads to bidding strategies and keyword selections that reduce traffic quality rather than improving it.
Impressions
Impressions measure how many times your ad was displayed. They’re useful for understanding reach and brand awareness at scale, but for most ecommerce businesses running direct-response campaigns, impressions alone are a vanity metric.
High impression counts can feel reassuring – your ads are ‘out there’ – but if those impressions aren’t translating into clicks, conversions, and revenue, they’re not doing meaningful work. Chasing impression volume can also lead to broader, less targeted campaign structures that dilute quality.
CTR (Click-Through Rate)
Click-through rate measures the percentage of people who see your ad and click on it. It’s a useful indicator of ad relevance and creative quality – but it’s a means to an end, not the end itself.
A high CTR on an ad that drives unqualified traffic is actively harmful: you’re paying for clicks that won’t convert. Conversely, a lower CTR on a tightly targeted, high-intent keyword set might be entirely appropriate if those clicks reliably convert at a strong value.
The Bigger Picture
Of course, there’s no single way of ‘correctly’ tracking, and no metric can claim to be the ‘best’ or the ‘worst.’ However, the metrics you do choose to track aren’t just a measurement decision – they shape how your whole PPC strategy gets managed. When the wrong numbers sit at the top of your dashboard, campaigns get pulled in directions that feel logical but don’t create real business value.
The most effective ecommerce PPC strategies share a common trait: they’re anchored to business outcomes (revenue, profit, growth) rather than channel metrics (clicks, impressions, CTR). The channel metrics have a supporting role – they help diagnose problems and understand what’s driving results – but they never take the wheel.
If you’re not sure whether your current PPC reporting is focused on the right things, it’s worth taking a step back and asking: if every metric on this dashboard looked good next month, would the business definitely be in a better position? If the answer isn’t a confident yes, it might be time to revisit what you’re measuring.
At Circus PPC, helping ecommerce businesses build reports that actually reflect performance – not just activity – is a big part of how we work with clients. If you’d like to talk through how your current setup stacks up, drop us a line.
