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2 min readUpdated Sep 8, 2026

How To Calculate True Roas

True ROAS in Causality Engine is calculated by dividing incremental revenue by marketing spend, reflecting the real return on ad spend for Shopify brands.

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Quick Answer·2 min read

How To Calculate True Roas: True ROAS in Causality Engine is calculated by dividing incremental revenue by marketing spend, reflecting the real return on ad spend for Shopify brands.

Read the full article below for detailed insights and actionable strategies.

The numbers behind the problem

iOS tracking loss

40-60%

Google Brand cannibalization

67%

Klaviyo overstatement

5x

TikTok attribution lag

21 days

Introduction

Return on Ad Spend (ROAS) is a key metric, but traditional ROAS often overstates performance by ignoring incremental impact. True ROAS corrects this.

Formula for True ROAS

[ \text{True ROAS} = \frac{\text{Incremental Revenue}}{\text{Marketing Spend}} ]

Where:

Incremental Revenue = Revenue caused by the marketing channel, estimated by Bayesian causal inference.

Marketing Spend = Actual spend on the channel.

Step 1: Calculate Incremental Revenue

Use Causality Engine’s incremental conversions estimate.

Multiply by average order value (AOV) or revenue per conversion.

Step 2: Gather Spend Data

Import accurate ad spend data per channel or campaign.

Step 3: Compute True ROAS

Divide incremental revenue by spend.

Compare against traditional last-click ROAS for context.

Why True ROAS Matters

Reflects genuine channel efficiency.

Excludes cannibalized or wasted spend.

Supports smarter budget decisions.

Example

If Facebook Ads generated 100 incremental conversions with AOV €50 and spent €3000:

[ \text{True ROAS} = \frac{100 \times 50}{3000} = \frac{5000}{3000} = 1.67 ]

Traditional ROAS might be higher due to over-crediting.

Pair with Refinement Queue to prioritize channels by True ROAS.

Learn more about marketing attribution at Wikidata.

Conclusion

True ROAS provides an accurate profitability measure, essential for scaling Shopify brand marketing.

Calculate True ROAS

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Frequently Asked Questions

How is incremental revenue different from total revenue?

Incremental revenue only counts conversions caused by the channel, excluding those that would have happened anyway.

Can True ROAS be less than 1?

Yes, indicating the channel is not generating enough incremental revenue to cover its spend.

Does Causality Engine calculate True ROAS automatically?

Yes, it provides True ROAS metrics in reports and exports.

Should I rely solely on True ROAS for budgeting?

True ROAS is critical but should be combined with qualitative factors and strategic goals.

Is True ROAS comparable across channels?

Yes, since it measures causal profitability, enabling objective channel comparison.

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