Whether agents are active, inactive, or deleted does not impact metrics in reports and views based on queue metrics. The Interactions view, Queue Performance Summary view, and Queue Performance Detail view even allow you to filter by specific active and inactive users.

Only active agents appear on agent-based views, such as the Agents Performance views. For agent-based reports, such as the Interaction Details report, you can select only active agents when you create a new report. However, if you already selected an inactive or deleted agent on a report while the agent was still active, then that agent still appears on the report when it runs. 

For more information about inactive and deleted agents and users, see Add people one at a time and Remove someone from your organization.