Planning and measurement

Attributed ROAS vs MER

Attributed ROAS uses revenue credited by one platform. MER uses total store revenue and total marketing spend. Neither is automatically incremental profit.

60-second answer

Use three views without blending their claims.

View	Numerator	Best use
Attributed ROAS	Revenue credited by one platform	Optimization inside that attribution system
MER / blended ROAS	Total store revenue	Store-wide efficiency trend
Contribution profit	Revenue less variable costs and ad spend	Profitability and scenario decisions

Do not add revenue claimed by Meta, Google, Amazon, or TikTok. Attribution credit is not exclusive, and each platform can use a different event time, window, and value definition.

Compare scenarios on contribution profit

Worked example

$120,000 of platform credit can reconcile to $100,000 of sales.

A store records $100,000 in net sales and $25,000 in total marketing spend. MER is 4.0x. Google credits $55,000 on $12,000 spend, while Meta credits $65,000 on $13,000 spend.

Report	Revenue	Spend	Ratio
Store / MER	$100,000	$25,000	4.00x
Google attributed	$55,000	$12,000	4.58x
Meta attributed	$65,000	$13,000	5.00x
Platform claims added	$120,000	$25,000	Not a store total

The extra $20,000 is overlapping credit or a definition/timing difference, not additional store revenue. MER still does not show profit because it omits product, fulfillment, fee, and return costs.

Monthly reconciliation

Compare like windows before interpreting the gap.

Freeze a date range and record whether reports use order date, click date, or conversion date.
Export total store revenue on a documented net or total-sales basis.
Collect all marketing spend, including channels that do not claim attributed revenue.
Record each platform's attributed value, model, window, and timezone separately.
Wait for conversion delay, refunds, cancellations, and reporting adjustments to mature.
Explain the gap before changing targets; do not force reports to match by deleting inconvenient rows.

Boundary: MER is an efficiency ratio, not a synonym for profit. Attributed ROAS is a platform reporting output, not proof that every credited sale was caused by the ad.

Source and limits

Keep platform facts separate from the business judgment.

Shopify documents marketing reports and the attribution concepts used in its reporting. ROAS Break's recommendation to keep platform credit, store revenue, and contribution profit separate is a modeling judgment designed to prevent double-counting.

Shopify marketing reportsMarketing reporting and attribution context. Checked August 20, 2026.