Developing
Sponsored by Optmyzr, which sells tools; the comparison is between two groups, not a controlled experiment.
In 60 seconds
- In BFCM 2024, CPCs rose 34% for advertisers using adjustments versus 17% for those who did not.
- ROAS fell 15.7% with adjustments and rose 5.7% without.
- The conversion value advantage from adjustments shrank from about 25 points in 2022 to about 6 points in 2024.
- The author says adjustments on predictable events push bids higher on top of what Smart Bidding already expects, and suggests changing tROAS targets for more volume.
Impact Layer
- What changed
- Seasonality adjustments, a feature many advertisers use for Black Friday, are being linked to overbidding.
- Why it matters
- Google's Smart Bidding already learns from past seasons, so an extra adjustment can double count the lift.
- Who is affected
- Google Ads advertisers and agencies preparing for November.
- Martech stack area
- Analytics, Advertising
- Stack impact
- Review whether you need seasonality adjustments this year and set CPC and pacing alerts. Use them for unexpected events such as flash sales.
- Business impact
- Moderate Sponsored content on MarTech by Optmyzr, which sells the tools it promotes; MarTech neither confirms nor disputes the conclusions. The headline says 5,000+ accounts and the body 5,886; adjusting advertisers may differ in other ways.
- Related technologies
- Related vendors
- What to watch
- Independent tests of seasonality adjustments in 2026.
MarTech published an article by Optmyzr, as sponsored content, on October 15, 2026. It reports Optmyzr’s analysis of Google Ads accounts for the Black Friday-Cyber Monday (BFCM) periods of 2022 to 2024.
Method
5,886 accounts in 2024, covering tens of billions of impressions over three years. Each BFCM period, from the Wednesday before Black Friday through the Wednesday after Cyber Monday, is compared with a pre-holiday baseline, and advertisers who set seasonality adjustments are compared with those who did not.
Findings (2024 unless noted)
- CPCs rose 34% for advertisers using adjustments, versus 17% for those who did not.
- ROAS fell 15.7% with adjustments and rose 5.7% without.
- The conversion value advantage from adjustments shrank from about 25 points (2022) to about 6 points (2024).
- Conversion rate lift without adjustments fell from 17.5% (2022) to 11.9% (2023) to 7.5% (2024).
Recommendations in the piece
Use adjustments for events Google cannot anticipate, change tROAS targets directly if you want more volume, and set guardrails: review pending changes, check for double-counted conversions, segment products by economics and set CPC and pacing alerts.
Caveats
It compares two groups and is not a controlled experiment. Optmyzr sells the tools it promotes, and the expert quotes are anecdotal.
Our read
The mechanism is plausible. Test one account with and without the adjustment before November.
Sources
- MarTech (sponsored by Optmyzr): We analyzed 5,000+ Google Ads accounts, Seasonality adjustments backfire on Black Friday (opens in a new tab)
Source for the analysis, figures and caveats.