Optmyzr BFCM Seasonality Insights

Are Seasonality Adjustments Really Worth It During BFCM?

Every year, as Q4 approaches, the advice lands in advertisers’ inboxes with predictable regularity: “Use seasonality adjustments to prepare for Black Friday and Cyber Monday.” On the surface, it seems sensible — you anticipate a surge in conversions, so you instruct Smart Bidding to act more aggressively. Yet Optmyzr’s latest analysis challenges this widely held belief, showing that these adjustments may often do more harm than good.

The Study at a Glance

Over three BFCM periods from 2022 to 2024, Optmyzr examined up to 6,000 advertisers annually. The research split accounts into two groups: those that used seasonality bid adjustments and those that did not. The study sought to answer a straightforward question: do these adjustments actually help advertisers capture more value during peak retail events, or are they simply prompting Google to bid higher without delivering meaningful gains? The findings suggest that the latter is often the case, particularly when efficiency and profitability are considered.

Smart Bidding Already Anticipates Peaks

One of the clearest insights from the study is that Smart Bidding largely anticipates the Black Friday and Cyber Monday conversion surge without any manual intervention. Advertisers who skipped seasonality adjustments still saw notable conversion rate increases over the three years: 17.5% in 2022, 11.9% in 2023, and 7.5% in 2024. Essentially, Google’s algorithms are already trained on historical data, allowing them to adjust bids dynamically based on real-time signals, rendering manual seasonality prompts largely redundant for predictable events.

The Cost of Manual Adjustments

Applying seasonality adjustments tells Google’s bidding system to increase bids by a predicted percentage. While this might seem logical, the study showed that it often leads to unnecessary cost inflation. CPCs consistently rose much faster for advertisers using these adjustments: for example, in 2022, CPCs climbed 36.7% with adjustments compared to 17% without. Across all three years, using seasonality adjustments roughly doubled the rate of CPC increase, without a proportional lift in conversions.

Efficiency Suffers

With CPCs rising faster than conversions, ROAS inevitably declines. The study found that advertisers who applied adjustments suffered steep drops in ROAS: -17% in 2022, -10% in 2023, and -15.7% in 2024. Meanwhile, the accounts that relied solely on Smart Bidding maintained stable or even improving ROAS, demonstrating that manual intervention can undermine profitability, even during high-revenue periods.

Why Seasonality Adjustments Can Misfire

Optmyzr explains that the problem stems from overprecision. Seasonality adjustments require advertisers to predict the exact lift in conversions. If the forecast is slightly off, Smart Bidding takes the estimate literally, leading to overbidding. For Black Friday and Cyber Monday, Google already has years of historical data baked into its models, meaning the algorithm typically knows exactly what to expect. This makes manual adjustments redundant and, in some cases, counterproductive.

The Trade-Off: Revenue vs Efficiency

Despite the ROAS concerns, the study showed that seasonality adjustments can drive higher revenue. For instance, in 2022 and 2023, revenue growth for adjusted accounts was significantly higher than for non-adjusted accounts, sometimes nearly doubling. This highlights a key trade-off: if your objective is to maximise market share, move inventory quickly, or grow top-line revenue aggressively, adjustments may make sense. However, if maintaining cost efficiency and profitability is a priority, they can be detrimental during predictable events like BFCM.

When Seasonality Adjustments Make Sense

Optmyzr emphasises that seasonality adjustments are not inherently flawed. They work best in cases where advertisers have insights that the platform does not, such as short flash sales, unique one-time promotions, large email campaigns, or niche events without historical precedent. In these scenarios, adjustments can provide real value by signalling temporary shifts in conversion behaviour that Smart Bidding might not detect immediately.

Situations Where Adjustments Are Less Useful

For predictable, recurring events like Black Friday, Cyber Monday, Christmas shopping, or Valentine’s Day, adjustments often do little to improve performance. Google’s algorithms already anticipate the lift in conversions, so manually telling the system to bid higher can result in overbidding, inflated CPCs, and reduced ROAS. In these cases, relying on the algorithm while monitoring campaigns carefully is usually the better approach.

Practical Guidance for PPC Managers

The study offers clear guidance for advertisers preparing for peak season. First, for most campaigns, it’s advisable to avoid applying seasonality adjustments for BFCM, allowing Smart Bidding to handle conversion spikes naturally. Historical data shows that this approach leads to steadier ROAS and avoids unnecessary cost inflation.

Communicating the Trade-Offs

If company leadership insists on prioritising revenue growth over efficiency, Optmyzr’s data provides a concrete way to frame the conversation. Managers can set expectations by explaining that adjustments can increase revenue but often reduce ROAS by 10–17 percentage points. This helps teams make informed decisions rather than simply reacting to a tactical recommendation.

Focus on Guardrails, Not Predictions

Rather than trying to predict exact uplift, advertisers add more value by implementing campaign guardrails. Key strategies include smart budget pacing, hourly monitoring with automated alerts, setting bid caps when necessary, checking audience and device segmentation, and ensuring creative and offers are optimised. Human oversight in these areas often outweighs speculative adjustments.

Key Takeaways

Optmyzr’s study shows that context is everything. Seasonality bid adjustments are not inherently bad, but using them for highly predictable retail events tends to reduce efficiency. For unique or brand-specific spikes, they remain a valuable tool. This research provides PPC managers with the data needed to take a measured, strategic approach during peak periods.

Confidence in Decision-Making

With this data, PPC managers can confidently answer questions about whether to enable seasonality adjustments during BFCM. For most advertisers, the answer is clear: trust Smart Bidding, monitor performance, and reserve manual adjustments for exceptional situations where you have insights the system lacks.

Preparing for a Smarter Peak Season

Ultimately, Optmyzr’s research provides a roadmap for approaching Black Friday and Cyber Monday strategically. Instead of overreacting to advice, advertisers can make informed, data-driven decisions that balance revenue growth with efficiency. Smart Bidding remains the cornerstone, and manual intervention should be reserved for truly unpredictable scenarios, ensuring campaigns remain profitable while maximising potential.