Begin Pondering ‘Begin-to-Render’ Impression Counting

The rendered ad future just got a bit more nuanced following proposals for new measurement standards from the IAB and MRC.

During the Austin Publisher Forum in August 2016, a swath of ops professionals gathered for a breakout on an issue that was only beginning to breach the surface. Discrepancies were on the rise as publishers were reporting that several demand ad servers were counting impressions on the basis of whether the creative had been rendered or downloaded. At the time IAB and MRC measurement standards stated that a standard impression counted when served (except for mobile in-app, though that was changed). 

In many cases, demand-side ad servers supply clients with both served and downloaded creative metrics in order not to limit advertisers from buying publisher inventory on a CPM basis. Flashtalking Chief Product Officer Joseph Pamboris says that the demand-side ad servers are only acting as auditors. It would seem the media agency and advertiser clients were putting additional pressure on their pub partners.

The tension only increased as DoubleClick For Publishers announced that it would be providing metrics on downloaded impressions for DFP clients in November 2016, the first phase of a three-part plan to move to solely counting downloaded impressions. That meant an impression would only be tallied if the content neighboring the ad, the ad server tag, and the creative to be served had been downloaded.

A future with only downloaded or rendered impressions counted suggested an even bigger increase in discrepancies as demand- and sell-side ad servers disagreed on when an ad had finished loading. But even worse, the change would likely cut heartily into publisher’s inventory when heavy creative from the advertiser tended to be the culprit for slow loads. 

But in late 2016, the IAB and MRC (with a little help from the MMA) threw a curveball by proposing that impressions for desktop display, mobile web and mobile in-app be measured on a “count-on-begin-to-render” basis. While different ad servers have various names for the start of ad rendering, it is a clearly defined and consistent event—unlike the completion of rendering. The IAB does not believe this will require a major tech augmentation from ad servers; in fact, Google’s GPT tags already feature a “start rendered” metric. 

Counting on a fully loaded or rendered-impression basis is inherently unfair to publishers because too many factors our out of their control. The IAB notes that not every party within the transaction can record or even know the “end state event.” Monitoring when such event occurred would require javascript regularly checking on the state of an ad—even with a limited amount of ads, this would chew up user CPU, slowing down browsers and siphoning away mobile battery. 

Pamboris adds that elements within an ad may be reeling in images (e.g., pictures of recently viewed products) from external locations or require user interaction to load completely. 

Reviewing data, MRC representatives found little difference between counting based on “begin-to-render” versus fully rendered. However, variations in counts based on “begin-to-render” and those based on downloaded ads proved “significant.” In addition, the agency notes that a “begin-to-render” requirement will bring display ads into line with video ads, which are not counted until they render post-buffering. 

“We anticipate this may become more important when we address cross platform measurement,” says David Gunzerath, Senior VP and Associate Director at the MRC.

According to Pamboris, the proposed counting metric will have a noticeable effect on the mobile space, where served and rendered impression counts can differ by upwards of 20%. 

“It is disconcerting for a marketer to see that more than 20% of mobile display impressions didn't even get to the count-on-download stage,” he says. “The 'race to the bottom' for CPMs and ad placement quality needs addressing, so I agree with what the MRC and IAB are doing here.”

The measurement proposals are open for public comment until Feb. 1, 2017. If endorsed, the MRC estimates industry adoption may take a year, but a “begin-to-render” standard would complement the viewability standard. Neither IAB nor MRC believe there will be a call or need in the near future to move to a fully rendered requirement. At the same time, it’s unclear when or whether RTB-based transactions will shift to the same standard.

Yes, publisher, this change in measurement will affect your inventory and impression counts a bit, but less so for those that made major redesigns and protocol alterations in the face of viewability. At the same time, here are some simple steps for a better existence in a "begin-to-render" world.

  • Adjust your ad specs (and then enforce them) to ensure faster ad loads. 
  • Encourage agencies to move the impression-tracking pixel (and the viewability one, for that matter) to the start of the ad call.
  • Talk to your ad server about how to make ad calls speedier, but consider granular targeting criteria will slow down ad loading.


Gavin Dunaway is Editorial Director of AdMonsters, heading up all website and print content as well as planning agendas for conferences like the Publisher Forum and Ops. Previously he served as Senior Editor for interactive advertising trade news depot Adotas.com, and before that he held reporting and editing roles for numerous industry-related publications. When not diligently producing news and feature articles related to ad ops, he enjoys playing guitar so loud that the walls shake. Follow him, if you dare, on Twitter at @AdMonsterGavin.


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