📉 stop obsessing over ROAS: the 3 metrics that actually matter

I had a chat with a client yesterday who was panicking over one bad ROAS day. It is easy to spiral when you are staring at Ads Manager all day.

Why your daily Meta ROAS is lying to you (and what to track instead)

If you're checking your Meta Ads Manager every morning watching ROAS bounce around, you're optimising for the wrong thing.

Here's the truth: attribution is broken.

When you're running Meta + Google + Email, the same sale gets claimed by multiple platforms. You can't add up those ROAS numbers and expect them to reflect reality.

So what should you track instead?

The 3 Metrics That Tell the Real Story

1. MER (Marketing Efficiency Ratio)

Total Revenue ÷ Total Marketing Spend (all channels)

MER is the only metric that can't lie. It doesn't care which platform gets credit. It just asks: "Did we make more money than we spent on marketing?"

Target: 3.5x to 4.5x for most eCommerce businesses

MER cuts through attribution mess and shows true marketing efficiency across your entire stack.

2. CAC (Customer Acquisition Cost)

Total Marketing Spend ÷ New Customers Acquired

CAC tells you what each customer actually costs to acquire across all channels.

The critical question: Can you afford this CAC relative to your Average Order Value?

Rule of thumb: Keep CAC under 33% of your AOV, ideally 25%

3. AOV (Average Order Value)

Total Revenue ÷ Total Orders

AOV is the other side of the profitability equation. When CAC rises, increasing AOV saves you.

Boost AOV through:

• Bundles and multi-buy offers
• Free shipping thresholds
• Checkout upsells
• Promoting higher-ticket products

The healthier your AOV relative to CAC, the more profitable your ads.

Why This Matters When You're Multi-Channel

When a customer sees your Instagram ad, Googles your brand, gets your email, then buys via a Google ad, every platform claims credit for the sale.

Meta says 4x ROAS. Google says 5x ROAS. Your email platform counts a conversion.

But you can't count the same sale three times.

MER solves this. It measures the whole system, not individual platform claims.

Your New Weekly Habit

Stop: Checking ROAS daily across platforms

Start: Tracking these three metrics every Monday

• MER → Is overall marketing efficient?
• CAC → Can I afford to acquire customers?
• AOV → Are customers buying enough per order?

If MER is healthy, CAC is sustainable, and AOV is growing, your business is profitable regardless of what platform dashboards say.

When Platform ROAS Is Actually Useful

Use platform ROAS for:

• Comparing campaigns within the same platform
• Identifying winning creative
• Budget allocation within Meta or Google

Don't use it for:

• Measuring true profitability (use MER)
• Comparing performance across platforms (attribution overlap)
• Strategic business decisions (use CAC/AOV)

The Bottom Line

Track these three metrics weekly:

MER → Overall marketing efficiency
CAC → Cost to acquire each customer
AOV → Revenue per order

Keep MER above 3.5x and CAC under 33% of AOV, and you'll have a profitable business.

Simple, honest, actionable.

This tracking system is exactly what we build in How We Convert. Real metrics. Real profitability. No attribution guesswork.

🎁 The Freebiz 

Here is a simple calculator spreadsheet to help you track your weekly MER without needing a maths degree.👉 Get the MER calculator

Thanks for reading me,

Michael from HWC 🤓

P.S. ROAS is often vanity. Profit is sanity. Kee