5 overlooked newsletter metrics that actually matter

For most newsletter teams, success is still measured in a tight loop of open rates and click-throughs. These headline stats are easy to track and simple to report—but they only scratch the surface of what really drives newsletter performance.

In a world where newsletters are central to audience engagement, first-party data, and revenue, it’s time publishers went deeper. The most successful email strategies are built on nuanced, actionable insights—many of which are still overlooked in most reporting dashboards.

Here are five newsletter metrics that might not get the spotlight, but can transform your understanding of what’s working, what’s not, and where real opportunity lies.

1. Net openers over total opens

Since Apple Mail Privacy Protection (MPP) blurred the accuracy of traditional open rate tracking, relying on open rates alone has become riskier. What matters more now is net openers—the actual number of unique subscribers opening emails over time, regardless of inflated signals from privacy proxies.

Why it matters: Net openers give you a more grounded, trend-aware view of your real engaged audience. Tracking this figure across several campaigns reveals shifts in loyalty and signals whether your newsletter is becoming a habit—or drifting into irrelevance.

2. Scroll depth or read time

Click-throughs measure action, but scroll depth or read time measures attention. A subscriber who doesn’t click might still be deeply engaged—reading, scrolling, digesting the content, and forming a habit.

Why it matters: This metric helps distinguish passive subscribers from truly engaged ones. If your newsletter is rich in editorial or analysis (and not just link-based), scroll depth is a better proxy for value. It tells you whether people read what you wrote—not just opened the email.

3. Unsubscribes by section or segment

A sudden spike in unsubscribes is often blamed on subject lines or send frequency. But the real insight comes when you can attribute unsubscribes to specific segments or content sections. Did a new layout alienate casual readers? Did a new feature turn off loyal subscribers?

Why it matters: By tying unsubscribes to content decisions or audience types, you can iterate smarter. It also helps you identify which segments may need separate treatment—whether that’s a lighter version, a different tone, or more focused content.

4. Time between opens

Tracking how many subscribers open multiple consecutive newsletters is good. But tracking how long it takes them to open the next one is better. This “time between opens” metric shows how close your newsletter is to becoming a habit.

Why it matters: Shorter intervals between opens suggest deeper loyalty and habit formation. Longer intervals may point to content fatigue or timing issues. Optimising for this metric helps you engineer consistency—one of the strongest predictors of retention.

5. Inactive but subscribed

Every list has “ghost subscribers”—users who don’t open, click, or engage, but haven’t unsubscribed either. It’s tempting to ignore them, but this cohort is full of opportunity. Some may just need a nudge; others are dragging down deliverability and inflating costs.

Why it matters: Identifying and understanding this group helps you run effective re-engagement campaigns. It also improves list hygiene, ensuring your performance metrics reflect reality—not bloated numbers.

Some publishers even re-segment this group into “sleepers” (who were once active) and “never actives” (who never engaged), offering tailored content or sunsetting tactics to each.

Don’t just report—investigate

Metrics should guide action, not just fill reports. By going beyond basic KPIs and looking at behaviour, timing, and patterns, publishers can turn newsletters from passive content channels into active growth engines.

The newsletters that drive the most revenue, loyalty, and insight aren’t just those with high open rates—they’re the ones optimised for habits, attention, and ongoing reader satisfaction.

So next time you’re reviewing newsletter performance, dig a little deeper. The best stories aren’t always told by the most obvious numbers.