“What’s the Most Important KPI?”
- Kai Zeyher
- May 27
- 2 min read
The uncomfortable truth: all of them.
This is one of the most common questions in email and CRM strategy:
“What KPI should we care about most?”
The honest answer?
They all matter, because they form a dependency chain.
You can’t optimize one while ignoring the others.
The KPI Stack (And Why Skipping a Layer Breaks Everything)
Think of email performance as a system, not a scoreboard.
1. Deliverability
If your emails don’t land in the inbox, nothing else matters. No opens. No clicks. No conversions. Just shouting into the void.
2. Open Rate
If opens are low, your audience isn’t seeing your message or your subject lines aren’t earning attention.
No opens = no opportunity.
3. Click-to-Open Rate (CTOR)
This is where content quality shows up.
If people open but don’t click, your message failed to deliver on the promise of the subject line. The gap between expectation and value lives here.
4. Unsubscribe Rate
This is long-term health.
High unsubscribes mean:
You’re over-sending
You’re under-delivering
Or you’re no longer relevant
It’s the clearest signal of perceived value over time.
A Brief Nerdy Aside (Bonus Factoid)
“Click Rate” is often treated as a standalone metric.
In reality, it’s just:
Open Rate × Click-to-Open Rate
Which makes it useful for reporting, but terrible for diagnosis.
If Click Rate drops, you don’t know whether:
Nobody opened
Or nobody clicked after opening
That’s why serious teams look at each layer independently.
The Real KPI Is Balance
Chasing one metric in isolation creates blind spots:
Aggressive subject lines boost opens but kill trust
Over-personalization increases clicks but raises unsubscribes
Over-sending boosts short-term engagement and long-term list decay
Healthy programs optimize the system, not the headline number.
Because in CRM and healthcare marketing, success isn’t loud, it’s sustainable.
Want to move the needle on all of your KPIs?
Get engaged customers and keep them?
