Scatter Plot for Ad Spend ROAS — Marketing Spend vs Revenue Diminishing Returns
An ad spend scatter plot maps campaign expenditure ($X$) against generated revenue ($Y$) and fits a linear OLS trendline whose slope $m = \Delta Revenue / \Delta Spend$ estimates incremental Return on Ad Spend (iROAS).
Tip: Paste Excel or Google Sheets rows (Ctrl+V / ⌘V) directly into any cell.
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Blended ROAS = sum(Revenue) / sum(Spend). Marginal (Incremental) ROAS = slope m = d(Revenue) / d(Spend). Organic baseline estimate = intercept b.
Chart Design & Use-Case Tips
- 01Blended ROAS = sum(Revenue) / sum(Spend). Marginal (Incremental) ROAS = slope m = d(Revenue) / d(Spend). Organic baseline estimate = intercept b.
- 02The regression slope $m$ represents your marginal/incremental ROAS (how many extra revenue dollars each additional $1 of ad spend generates), while the y-intercept $b$ estimates baseline organic revenue at $0 ad spend.
- 03If high-spend points bend below the straight regression line, your channel is experiencing diminishing marginal returns (audience saturation).
- 04Use for Google Ads, Meta Ads, and Media Mix Modeling (MMM) calibration.
Frequently Asked Questions
What is the difference between Average ROAS and Marginal ROAS (slope m)?+
Average ROAS divides total revenue by total spend (including baseline conversions that would have happened anyway). The regression slope m isolates incremental revenue per additional dollar of spend.
How do I spot ad fatigue or saturation on the scatter plot?+
When the rightmost points (highest weekly spend) flatten out below the linear trendline, incremental spend is yielding lower marginal returns.
Can I plot individual ad campaigns instead of weeks?+
Yes, enter each campaign name in the Label column, its spend in Series A, and its revenue in Series B.