What’s the impact of hygiene on open and click rates?

Open rates and click rates don't just measure how interesting your emails are. They're shaped by where your emails actually land. And where they land depends heavily on list hygiene.

Here's the chain of events that most senders miss. When you keep sending to unengaged contacts, invalid addresses, or addresses with high complaint history, mailbox providers like Gmail start treating your sending domain as lower quality. They route more of your emails to spam or Promotions. Fewer people see your emails. Your open and click rates fall. That lower engagement then signals even less trust to the mailbox provider. It cycles.

The direct effects of poor hygiene on your metrics:

• Higher denominator, lower rates. If you're sending to 50,000 contacts but 20,000 of them can't or won't engage, your open rate is calculated against that full 50,000. Clean out the non-engagers and your reported rate goes up even without changing anything about your emails.
• Inbox placement drops first, then opens. You might not notice the inbox placement problem immediately. But a couple of campaigns later, opens will start sliding as fewer people see your messages at all.
• Complaint signals hurt future campaigns. Every spam complaint from a bad address (or a resentful old subscriber) shaves a little off your sender reputation. The emails you send after that complaint start with a slight disadvantage.

Conversely, when you clean your list regularly (removing hard bounces promptly, sunsetting long-term non-openers, and validating new addresses at signup), your metrics reflect the subscribers who actually want what you're sending. That's when open and click rates start to mean something useful.

Worth checking: Google Postmaster Tools shows your domain reputation and spam rate for Gmail traffic. If your Postmaster Tools score is dropping at the same time as your opens, that's the connection. Start with list hygiene before blaming your subject lines.