PMax Channel Distribution Alert

Track how your Performance Max spend shifts between Search, Shopping, Display and Video.

This script monitors how your Performance Max campaigns spend across four channels (Search, Shopping, Display and Video), comparing a short rolling period (default 7 days) against a longer baseline (default 30 days). If a channel's cost share changes more than your chosen threshold, the script flags it and emails you a summary per campaign.

What you will see

After connecting the script to a Google Sheet, it fills a 30-day summary tab with daily metrics per campaign and channel, creates a 7-day rolling summary tab that smooths out day-to-day noise, color codes the columns for easy scanning and auto-resizes columns for readability. This makes it easy to see spend, impressions, clicks and conversions per channel and how the mix changes over time.

How alerts work

For each campaign the script compares the latest rolling period with the longer baseline, looks at the share of cost per channel rather than absolute spend, ignores tiny volumes to avoid noise, and triggers an alert only when the change exceeds your configured threshold. Alert emails include a summary of how many changes were found, which campaigns and channels are affected, a campaign-by- campaign breakdown with direction and size of the shift and a link to the Google Sheet.

What you can configure

• Which Google Sheet the script writes to.
• How big a change should be before you get an alert.
• The minimum number of impressions before a campaign is considered.
• How many days to use for the total analysis period and for the rolling average.
• Which email addresses should receive alerts.

When to use this script

Use it if you rely on Performance Max and want control over where the budget actually goes, need early warning when PMax shifts spend between channels, want a clean data export for deeper analysis in Sheets or Data Studio, or prefer a simple email summary over manually checking reports. It's especially useful for agencies and in-house teams managing multiple PMax campaigns.

Practical tips

• Start with a higher threshold like 20 percent to avoid too many alerts, then lower it if needed.
• Check the spreadsheet regularly to spot slow trends that might not trigger an alert yet.
• Use the 7-day tab for recent changes and the 30-day tab for context.
• Combine this with your normal performance reviews to decide whether to adjust assets, feeds, or budgets.