You simply don't.
This is the wrong question. Don't try to measure performance by using things like the number of Jira tickets closed or lines of code (LOC) written.
Measure the impact instead. The goal is not to have a busy product development team. The goal is to have real impact on your user base and your business.
How to measure impact?
- Retention rate / churn
- Number of active users
- Customer Lifetime Value (CLV)
- Monthly Recurring Revenue (MRR)
- Customer Satisfaction (NPS)
- Usage/ Time spend in app
To track the performance of your engineering teams, the metrics from Google's DORA research projects are boiling it down to the essence:
- Lead time - how long does it take to go from code committed to code successfully running in production?
- Deploy frequency - how often does your organization deploy code to production or release it to end users?
- Time to restore - how long does it generally take to restore service when a service incident or a defect that impacts users occurs?
- Change fail percentage - what percentage of changes to production or releases to users result in degraded service?