Is open rate still a useful metric?
Still have a question, spotted an error, or have a better explanation or a source we should cite?
It's useful, but it's not what it used to be, and knowing the difference matters.
Before Apple Mail Privacy Protection (MPP) launched in 2021, an open was a reasonable proxy for someone actually reading your email. When Apple Mail started pre-loading tracking pixels in the background (regardless of whether anyone actually opened the email), that signal broke for anyone with a significant Apple Mail audience. Open rates for many senders jumped 5-20 percentage points overnight and never came back down.
So what is open rate still good for?
Directional trends on the same audience. If your open rate was 30% last month and it's 15% this month, something probably changed (send time, subject line, deliverability issue, list health). You can't read the absolute number, but the relative change is still meaningful.
Comparing segments where MPP isn't the variable. If you're comparing open rates between Android users and iOS users in the same campaign, the difference is real. If you're comparing overall campaign open rates month over month, the MPP noise makes it harder to read.
What's actually more reliable now: click rate and click-to-open rate (CTOR). Clicks require an actual human action. They're harder to inflate and give you a cleaner signal of genuine interest. Reply rate is even stronger if your email invites replies.
Don't abandon open rate tracking entirely. Just don't let an inflated number fool you into thinking your engagement is stronger than it is.
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