The best indicator is the one that tracks user experience clearly enough to drive decisions.
User-facing, specific, measurable, and stable enough to compare over time.
Easy to collect, but disconnected from what the user actually notices or values.
User aligned
Captures what the user actually experiences.
Well specified
Defines good events and valid events precisely.
Actionable
Can support targets, alerts, and policy decisions.
Resilient
Not so noisy that it becomes political instead of useful.