Measure what people feel.
The only point of becoming more Agile is better outcomes. Measure those, not how Agile things look.
Vanity
Outcome
Number of teams “doing Agile.”
Lead time from idea to customer.
Certifications earned.
Deployment frequency and change failure rate.
Ceremonies held on time.
Customer satisfaction with what shipped.
A maturity-model score.
The team health trend (Day 89).
Measure outcomes customers and teams actually feel.