Troubleshoot the Performance Max channel performance report

To effectively understand Performance Max channel performance, it's essential to consider both your overall results and your individual channel insights. This approach is crucial because Performance Max dynamically optimizes across channels to achieve maximum campaign return in real time, targeting your core conversion goals.

This article explains potential patterns you may observe in your channel reporting while maintaining a focus on campaign-level performance. Additionally, it suggests actionable steps, when possible, to better align channel performance with your business goals.

Not serving or very low serving on certain channels
Performance Max shopping campaign has a low share of “Ads using product data”
Lower than expected return-on-investment (ROI) on a particular channel
Concerns about invalid traffic and high Display spend
High spend share on YouTube due to potential overvaluation of Engaged-view conversions (EVCs)
Lower than expected investment in Search
Spending primarily on Search with minimal investment in other channels

Potential scenarios and actions you can take

Not serving or very low serving on certain channels

Use the status column of your channel performance report to identify any issues that may be impacting a particular channel’s eligibility to show ads.

If no issues are present, then it's likely that you’re not serving on this channel because other channels are providing a higher ROI at the moment. Performance Max aims to maximize performance across channels by bidding on the inventory that’s predicted to deliver the most cost-efficient, highest ROI conversions in real time. This means spending on the channels that are expected to drive the best results for your particular goals and targets, and within your budget.

If you’re still interested in increasing your share of wallet on a particular channel, we recommend following our optimization tips for channel performance. While these recommendations don’t guarantee that your campaign will invest more in a particular channel, they can help maximize the potential that it will.

Performance Max shopping campaign has a low share of “Ads using product data”

In general, if you aren’t spending on a particular inventory type it means that Performance Max is able to drive more value via other inventory sources at that moment. However, it’s possible there may be issues or missing best practices causing a lower share of wallet on Shopping inventory:

Product feed issues: Use the status column of your channel performance report to identify any issues that may be impacting your ability to show Shopping ads.
Regular Shopping campaigns with the same product offers: If you also run regular Shopping campaigns alongside Performance Max and they have the same product offers, it’s possible that Performance Max isn’t serving or is serving less on Shopping because those products are being shown via other campaigns.
Missing best practices: If your campaign isn’t fully optimized on the Search channel, for example, if your asset strength is low or medium, this may also impact your ability to show Shopping ads. Refer to our optimization tips for channel performance.
Shopping inventory constraints: The available relevant searches for your products within Shopping might be limited, leading Performance Max to allocate more spend to other channels where there is more demand. If your campaign is not limited by budget this may be one reason your campaign isn’t able to scale spend further on Shopping.

If you’ve ruled out the possibilities above, then it’s likely that Performance Max is simply finding better opportunities to drive value via other inventory types at the moment. Performance Max aims to maximize performance across channels by bidding on the inventory that’s predicted to deliver the most cost-efficient, highest ROI conversions in real time. This means spending on inventory that is expected to drive the best results for your particular goals and targets and within your budget.

Lower than expected return-on-investment (ROI) on a particular channel

You may notice differences in the average ROI (CPA or ROAS) of different channels in your channel performance report due to several factors.

Differences in marginal ROI: When allocating budget across channels, Performance Max considers marginal ROI, which is the incremental return you can expect from each additional dollar spent. This means that Performance Max may allocate budget to a channel with a lower average ROI if that channel offers a higher return on your next dollar.
Conversion delay: When evaluating channel performance it’s important to take into account your conversion delay. Some channels are more impacted by conversion delay so it’s important to adjust your date range to exclude the conversion delay period in order to properly evaluate ROI at the channel level. Without accounting for conversion delay, a channel’s (and the overall campaign’s) CPA or ROAS will appear to be worse than it actually is, until the delayed conversions have been reported.
Cross-channel dynamics: If your campaign uses last-click attribution, it’s possible that a channel might appear to have a low ROI when in reality it's playing a crucial role in driving conversions on other channels. This is because the last-click attribution model often fails to capture the full impact of channels that contribute earlier in the customer journey. To improve how you’re capturing the impact of assisted conversions within Performance Max, consider implementing data-driven attribution.

Keep in mind that Performance Max is designed to maximize your overall campaign performance across all channels, not just the performance on any single channel. We recommend focusing on your campaign’s overall ROI, as channel-level ROI can be misleading due to the above factors, especially marginal ROI.

Concerns about invalid traffic and high Display spend

If you’re a lead gen advertiser or your campaigns are optimizing toward a shallow conversion it’s important to ensure a strong measurement foundation in order to drive quality traffic. Learn more about best practices for generating high-quality leads.

Even if you don’t have a lead gen business model, if you’re optimizing toward a non-purchase event, you should make sure to follow the best practices.

Keep in mind that Google continuously reviews traffic for new or previously undetected invalid traffic. When our system detects invalid traffic with your ads, we automatically filter these out of your reports. You're not charged for them and you still have the option to view the data. Learn more about managing invalid traffic.

High spend share on YouTube due to potential overvaluation of engaged view conversions (EVCs)

You can review how many engaged-view conversions (EVCs) are recorded in your campaign by segmenting the campaigns table by ad event type.

If you’re concerned that the volume of EVCs are too high, due to concerns around incrementality of EVCs, you can take the following steps:

Reduce your conversion window: A shorter conversion attribution window will count fewer EVCs. For example, you could set it to 1 day. Refer to about Engaged-view conversions for guidance on how to update your conversion window.
Track deeper conversions: Optimizing towards deeper conversion events (e.g. purchases) is likely to drive fewer EVCs than shallower conversion events like page views.

Why does Google Ads count EVCs?

Video is immersive and effective, but unlike other ad formats, users don't always interact with video ads in the moment — they often take action later, after their viewing session. Because users often don’t take action instantly, looking only at clicks drastically under-reports the value that video delivers. We’ve conducted large-scale incrementality studies to determine the optimal default conversion window for EVCs (three days), which is a good starting point for most customers.

Lower than expected investment in Search

Check the status column in your channel performance report to ensure there aren’t any outstanding issues flagged that may be limiting your ability to serve on Search.

Even if there are no blockers identified, you can use our optimization tips for channel performance to increase your campaign’s potential to drive strong results with Search.

Keep in mind that Performance Max is designed to maximize your overall campaign performance across all channels, not just the performance of any single one.

Spending primarily on Search with minimal investment in other channels

First check the status column in your channel performance report to ensure there aren’t any outstanding issues flagged that may be limiting your ability to serve on other channels.

Even if there are no blockers identified, you can use our optimization tips for channel performance to increase your campaign’s potential to drive strong results on channels besides Search.