Apple Recipe: Getting Around Inflated MPP Open Rates

Email open rates are continuing to rise because of the artificial inflation caused by Apple’s Mail Privacy Protection (MPP). And these increases are “material numbers for senders and not something that can simply be ignored,” writes George Schlossnagle, engineer and evangelist at SparkPost, in a Friday blog post. 

SparkPost has seen a consistent increase for unique email opens of “about 12% gross percentage points for most senders, with three quarters of customers seeing at least an 8% lift and one quarter seeing 15% or more,” Schlossnagle says.

This has thrown open-rate metrics off: As Schlossnagle puts it, “the open as a metric for measuring individual behavior or as a trigger in a workflow is now unsafe.” 

But Schlossnagle adds that the open rate is still is relevant and useful “as an aggregate take on group behavior.”

Of course, the best way around inflated opens is to measure clicks and conversions. But not all programs are doing that — yet.



One technique is to “remove all MPP opens from the data you’re measuring,” Schlossnagle contends. “Discard MPP opens from the numerator and remove deliveries that resulted in MPP opens from the denominator.” 

How is that stacking up? 

Based on our own eyeballing of the data, the average open seems to be slightly lower than 20% — an improvement over the end of December 2021, but a little lower than last October.  

“We do see a slight decline here over the measurement period (likely due to excluding so many active mobile users), but overall it is much more consistent and thus makes it a better metric to use as an indicator of positive or negative change.

Schlossnagle adds: “As MPP adoption has leveled off, we see just over a quarter of opens overall coming from MPP on average, and for three quarters of senders it’s less than 50%.” 

These numbers show why individual opens are no longer trustworthy. But they also prove that “a majority of your open data is still as useful as it was before — more than enough to use for the purpose of aggregate stats.” 

Schlossnagle says the death of opens is being exaggerated, but adds that "if we have additional large providers (specifically Gmail or VMG) move to pervasive pre-fetching, that should cause a reevaluation of things.”

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