Open Rates Are a Vanity Metric

In September 2021, Apple rolled out Mail Privacy Protection. It pre-fetches email content for all Apple Mail users, which registers an "open" even if the person never looked at your email.

Apple Mail accounts for 50-60% of email opens on most consumer lists. That means your open rates jumped 20-40% overnight without a single extra person reading your emails.

Why this matters

If you are reporting a 45% open rate to your team or clients, the real number is closer to 28-32%. The rest is Apple bots.

Worse: if you are making decisions based on open rates (A/B test winners, send-time optimization, re-send to non-openers), your data is polluted. You are optimizing based on machine behavior, not human behavior.

What to track instead

Click rate. Clicks are real actions. Apple MPP does not click links. When someone clicks, a human made a decision.

Revenue per email. This is the number that matters. Tie every email to downstream purchases. Most ESPs have attribution windows you configure (we use 5-day click, 1-day open).

Revenue per recipient. Total flow revenue divided by recipients. This tells you how well your automation performs per person entering it, which is the number that scales with list growth.

Unsubscribe rate. If it is above 0.3% per send, your content or frequency has a problem. This number is immune to MPP inflation.

How to fix your reporting

Stop using open rate as a primary KPI. It belongs in the appendix, not the headline.

Rebuild your A/B testing framework around clicks and revenue. Subject line tests should measure click-through, not open rate.

Fix your re-send logic. "Resend to non-openers" catches Apple MPP users who already opened. Use click-based re-engagement instead.

Update your segmentation. "Engaged" subscribers should be defined by clicks and purchases in the last 90 days, not opens.

The uncomfortable truth

Your real engagement is lower than your dashboard shows. That is not a bad thing to know. It means you have room to improve, and now you have accurate data to measure that improvement.