Google is slowly opening its black box — but marketers aren’t so convinced

For marketers, it’s a partial reveal — another piece of the puzzle but not the picture. There’s data. But context, as usual, remains elusive.

“When it first came out it was an opt-in type of beta, but now they’re making it more available which is nice,” said Michelle Merklin, vp of search innovation and growth at Tinuiti, which has hundreds of Google Ads clients — the majority of whom have already had access to this new Performance Max channel reporting.

But looks can be deceiving. A major challenge right now is the fact advertisers have access to this channel-level data through this new reporting, but without any ability to take action on the information they’re shown.

“I don’t think there’s a ton of value, other than being able to validate or find issues with Performance Max,” Merklin said.

Another challenge is the granularity. Merklin explained that while it’s helpful to see channel performance per campaign, there’s no way to see trends in aggregate across an advertiser’s Performance Max campaigns.

“A lot of times, clients will ask what trends we are seeing overall, but there’s no easy way for us to answer that question right now, without exporting every single campaign’s data manually and pivoting it out,” she explained. 

That fragmented view brings with it another risk: misinterpretation. As Shamsul Chowdhury, global evp of paid social at Jellyfish, noted, advertisers may overindex on what looks like a top-performing channel only to unintentionally break what was working. Performance Max works because of how placements blend. Marketers start tinkering with that and performance could collapse. 

“I applaud Google for providing that transparency, but I feel it’s going to backfire if advertisers start taking that approach,” Chowdhury said. “I think this [reporting] is a way for them [Google] to verify what they were telling advertisers before, but now they’re actually showing the data. But advertisers need to use it in the right way to inform their decisions, versus just putting everything into one placement that’s converting, otherwise they’ll miss out on the bigger picture.”

Enders Analysis’ senior research analyst, Jamie MacEwan echoed this. 

“The solution for advertisers who look at the reporting and really want to cut out an underperforming channel is to run separate campaigns targeting only the desired channels,” he explained. “But that is a lot of extra work and undoes the cross-channel and automation benefits of Performance Max if an advertiser has been getting globally good results from it.” 

How does video resonate in Performance Max?

Some advertisers have found that video isn’t such a big deal to their campaign performance after all — that’s despite short-form video being touted by the industry as the number one format across the board.

Merklin, for example, said that from what her team has seen so far, video is “a lot less of a big deal than Google wants us to think within Performance Max”. She explained that while many of Tinuiti’s clients have video assets loaded into their Pmax campaigns, they’re not driving a lot of volume through video. She did not provide specific figures.

But Tinuiti’s Q2 2025 benchmark report backed it up. According to the report, less than 10% of spend volume on Pmax comes from video inventory.

“There may be impressions coming from there, but very little conversion volume. And in some cases, very little impression volume,” she said. “We’re able to see that it really is more of a search campaign pipe than they [Google] had previously been positioning it as.” 

The channel performance reporting almost provides advertisers with the data to support their theories. “It lets us export the data directly so we can analyze it more and understand where the conversion rates are stronger on certain channels than others,” she added.

Responding to a request for comment, a Google spokesperson said: “Channel performance reporting in Performance Max is a direct response to advertiser needs for greater transparency. We initially launched this feature in beta to gather valuable feedback and to help advertisers make more informed decisions to optimize their campaigns. We’re encouraged by ongoing advertiser input as it continues to roll out.”