ROAS is the metric that makes teams feel calm.
It’s neat. It’s immediate. It turns marketing into something that looks controllable: spend goes in, revenue comes out, and the dashboard politely applauds you with a number.
MER is the metric that makes teams honest.
It doesn’t care which channel “won.” It doesn’t care which platform claimed the conversion. It looks at the business as a system and asks a tougher question:
Did our total marketing investment produce scalable revenue? Yes or no.
That’s why the real conversation around MER vs ROAS isn’t about which one is “better.” It’s about which one is telling you the truth for the decision you’re making, especially in telehealth, where journeys are long, messy, and heavily shaped by operational realities.
What ROAS Measures
ROAS: Return on Ad Spend measures the revenue generated by a channel or campaign relative to what you spent on it. In practice, it’s the metric you use when you’re diagnosing ad performance: creative, audience, bidding, offer, and landing page alignment.
If a campaign spends $50,000 and reports $200,000 in attributed revenue, the ROAS is 4.0. That’s a useful signal. It tells you there’s a revenue response happening that’s proportional to spend. It also tells you where to dig next: is it one ad? One audience? One placement? One message that’s doing all the work?
ROAS is exceptionally good at helping you improve what you can control inside a channel.
But ROAS has a limitation that becomes more pronounced in healthcare: it only measures what attribution can see.
In telehealth, attribution is rarely a clean reflection of causality.
What MER Measures
MER, the marketing efficiency ratio, moves up one level. It doesn’t ask which campaign drove what. It asks whether marketing as a whole is producing output that justifies the investment.
The marketing efficiency ratio vs ROAS distinction becomes obvious once you say it plainly:
ROAS is a channel diagnostic.
MER is a business scoreboard.
MER is calculated as total revenue divided by total marketing spend. That means it includes the full revenue generated by your marketing system and the full cost of operating it. It’s not a platform story. It’s your business story.
In telehealth, where multiple channels collaborate to create trust and intention often over days or weeks, MER is the metric that holds the whole ecosystem accountable without forcing you to pretend attribution is perfect.
You’re not trying to win the debate about who gets credit. You’re trying to grow efficiently.
Attribution Blind Spots in Healthcare
If you’ve ever looked at a telehealth conversion path and thought, “This makes no sense,” you’re not alone. Patients don’t move through healthcare decisions like retail shoppers. They research symptoms privately. They compare clinics. They read reviews. They consume educational content. They abandon intake. They return later. They convert after a provider review step. They refill later. They add treatments later.
Much of that behavior is either invisible to attribution systems or incorrectly attributed to the last thing that touched the user.
That’s why ROAS in telehealth often over-rewards bottom-of-funnel activity: retargeting, branded search, and “checkout rescue” ads because those touches happen right before conversion. They close the demand. They rarely create demand.
MER absorbs those blind spots by refusing to play the credit game. It measures total output versus total input. In regulated, trust-heavy journeys, that’s often closer to reality than any platform’s self-reported narrative.
When ROAS Can Rise While MER Falls
This is where teams get into trouble: the dashboard shows success, while the business is quietly weakening.
Imagine ROAS is improving month over month. Paid retargeting is efficient. Branded search campaigns are printing attributed revenue. On paper, the ad machine looks like it’s working better than ever.
Meanwhile, the business starts feeling… off.
New patient volume stops growing meaningfully. Conversion rates soften. Refunds creep up because fulfillment timelines are under strain. Support tickets increase. Retention slides because the experience isn’t retaining patients as it used to. Revenue growth is slowing, even though paid “performance” remains strong.
That’s how you get the split: ROAS up, MER down.
Because ROAS can improve when a channel gets better at harvesting existing intent, even if the overall system is producing less incremental demand and less sustainable revenue.
The reverse can also happen. You can see a temporary ROAS dip while MER holds steady. That often happens during responsible scaling phases when you expand audiences, test new offers, or invest in demand creation, attribution undercounts early on. The platform may not fully credit the incremental lift, but the business-level revenue output still improves relative to spend.
That’s why, in telehealth, treating ROAS as the ultimate truth is a category error. It’s one signal. It’s not the system.
When to Watch Each Metric
The goal isn’t to choose one metric and throw the other away. The goal is to assign each metric the job it’s actually qualified to do.
ROAS is what you watch when you’re tuning. When you’re asking, “Are these ads working? Are these audiences responding? Is this offer resonating? Is our creative fatigue showing up?” ROAS is fast feedback.
MER is what you watch when you’re making scaling decisions. When you’re asking, “Can we increase total spend without degrading efficiency? Are we buying better demand or just more demand? Is the business getting stronger as we grow?” MER is the growth truth test.
In telehealth, those questions are never purely marketing questions. Scaling spend impacts operations. Operations impact refunds and retention. Retention impacts revenue curves. Revenue curves feed back into MER.
Actionable Takeaway
If you want a simple rule that keeps teams out of metric-driven chaos, use this:
When you’re optimizing campaigns, trust ROAS.
When you’re scaling the business, trust MER.
Then track them together.
If ROAS improves and MER improves, you’re scaling a healthy system.
If ROAS improves and MER declines, you’re likely over-crediting closing channels while demand, retention, or operations degrade.
If ROAS dips but MER holds steady, you may be investing in growth the platform can’t fully attribute yet.
In subscription healthcare, the goal isn’t to win a dashboard.
It’s to build a growth system that scales without breaking trust, margin, or experience.
ROAS tells you where to tune.
MER tells you whether the whole machine is worth scaling.
References
- Google Ads Community. (n.d.). Explain ROAS [Online forum post]. Google Help. https://support.google.com/google-ads/thread/247427992/explain-roas
- AppsFlyer. (n.d.). Return on ad spend (ROAS). AppsFlyer Glossary. https://www.appsflyer.com/glossary/roas/
- Muzzi, M. (2025, October 29). Marketing efficiency ratio: How to calculate + improve MER. Shopify. https://www.shopify.com/blog/marketing-efficiency-ratio