You could use a issue statistics dashboard gadget.
Click on "Add gadget" on your JIRA dashboard and select the "Issue Statistics" gadget. Then select the project you want to track and set the "statistics type" to assignee.
Frage
I want to have a list of all the users on my project and the number of issues assigned to him/her. Is there a way to do this in JIRA 5.2.11?
Lösung
You could use a issue statistics dashboard gadget.
Click on "Add gadget" on your JIRA dashboard and select the "Issue Statistics" gadget. Then select the project you want to track and set the "statistics type" to assignee.