You can't measure performance of a developer by the following:
Hours worked
Lines of code
Bugs fixed
Tasks completed
Number of commits
Velocity points
Pull request count
Computer activity metrics
You need to measure the performance by the following steps:
Deployment frequency What it measures: How often an organization successfully releases to production. Measurement: Deployments per day. Impact potential: Increase customer value by reduced Time-to-Market.
Lead time
What it measures: How much time is between the beginning of a project’s development and its delivery to the customer. Measurement: Lead time in days. Impact potential: Increase project planning accuracy
Cycle time What it measures: How much time do individual project stages take. Measurement: Cycle time in days. Impact potential: Increase project planning accuracy
Lead time for changes
What it measures: How much time it takes a commit to get into production. Measurement: Lead time in days. Impact potential: Increase developer efficiency
Velocity
What it measures: The amount of work that your team can accomplish in a given amount of time (sprint). Measurement: Man-hours or story points. Impact potential: Improve project and sprint planning
Work-in-progress
What it measures: The the state of the work in progress. Measurement: Number of tasks in progress. Impact potential: Identify bottlenecks and sunk costs
Change failure rate
What it measures: The percentage of deployments leading to a degradation in service that must be addressed. Measurement: Number of incidents divided by number of deployments. Impact potential: Increase customer satisfaction by decreased number of outages
Time to restore service
What it measures: How long it takes an organization to recover from a failure in production. Measurement: Restore Time in hours. Impact potential: Increase customer satisfaction by decreased number of outages
Customer satisfaction score
What it measures: How satisfied a customer with your products or services. Measurement: Surveys with scales and open questions. Impact potential: Improve customer relations and satisfaction
Team health
What it measures: Distribution of work among team members. Measurement: Work items distribution in terms of type and quantity. Impact potential: Create fair team workload distribution