Your open rate is lying to you.
The number went up. The revenue did not.
Your open rate is lying to you.
A client I worked with last year opened our quarterly review thrilled. Their campaign open rate had climbed to about 58%, the best number their account had ever shown. They wanted to know what we had changed so they could do more of it. I had to walk them through the uncomfortable part: we had not changed anything that explained it, and the revenue from those campaigns had stayed flat. The number went up. The money did not follow. In the audit it was obvious why. A large share of those "opens" were machines, not people.
This is the conversation I have most often now. A founder is reading a metric that used to mean something and no longer does, and they are making decisions on it. Send-time tweaks, subject line tests, list re-engagement, all tuned against a signal that has quietly gone hollow.
Why the open rate stopped meaning what it used to
The break is Apple Mail Privacy Protection. When a subscriber on Apple Mail has it on, Apple pre-fetches the email's images through its own servers, in bulk, whether or not the person ever looks at the message. The tracking pixel that records an "open" fires on that pre-fetch. So the open gets logged for a human who may never have seen the subject line.
This is not a fringe case. Apple Mail accounts for around 49% of email opens (Litmus, January 2025), and roughly 64% of subscribers are on MPP-capable Apple Mail (Litmus 2025). When you stack the auto-opens on top of normal corporate scanners and security bots that also trip the pixel, the inflation is real and measurable: Litmus puts the lift at 15 to 35% depending on the list. In other words, a reported open rate can run a third higher than the human number underneath it.
The deeper point is what the metric now measures. An open does not tell you a person read your email. It tells you an inbox provider fetched an image. You are measuring infrastructure, not attention. For a list heavy on Apple users, the open rate is closer to a count of how many subscribers use Apple Mail than a count of who cared about your send.
What I track instead
The fix is not a better pixel. It is to stop treating opens as a primary metric and move to signals a machine cannot fake on a subscriber's behalf. These are the ones I put on the dashboard for every account.
Click-to-delivered. Clicks require a human hand. Measure unique clicks against emails delivered, not against opens, because the open denominator is the part that is polluted. This becomes your real engagement line. It will look lower than the open rate ever did, and that is the point: it is true.
Revenue per recipient. Total revenue attributed to a send, divided by recipients. This is the number that survives every platform change, because it is tied to money rather than to a tracking method. When the client above saw flat revenue per recipient against a rising open rate, that gap was the whole story.
Engaged segments by recency. Build segments on clicked or purchased in the last 30, 60, and 90 days, not opened. Opened-based segments quietly fill with Apple auto-opens, so your "engaged" audience inflates and your sunset logic stops working. Click and purchase recency keeps the segment honest, which protects your sender reputation when you mail it.
List health trend. Watch the unsubscribe rate and the complaint trend over time, not any single send. A healthy unsubscribe rate sits around 0.1 to 0.3% per send (industry benchmarks 2025 to 2026); above 0.1% complaints (1 in 1000) is Google's documented red line at Gmail. These move in the wrong direction long before revenue does, so they are your early warning that the list is tiring of you.
None of these are exotic. Every one of them is already in your ESP. The shift is deciding which number you let drive the calendar.
Where opens still earn a place
I am not telling you to delete the metric. A sudden collapse in open rate can still flag a deliverability problem, because if mailbox providers start routing you to spam, even the auto-opens stop firing. So a falling open rate is a useful alarm. A high open rate is just not a useful trophy. Read it as a smoke detector, not a scoreboard.
The hard part of this conversation is never the data. It is that someone has been reporting that 58% upward for a year, to a board or a partner or themselves, and the honest replacement number looks worse on the slide. But a worse number you can act on beats a flattering one you cannot. The client who saw the gap stopped optimizing for opens, rebuilt their segments on clicks and purchases, and within two quarters their revenue per recipient was something we could actually move. The open rate, we stopped mentioning. It was never the thing making them money.