Karma Plugin for JIRA
Karma Plugin for JIRA is created to calculate the risks of JIRA tickets to be reopened and thus to be able to recognize and mitigate risks of every release. Plugin uses the principle of yesterday's weather in a sence that it uses previously collected data about users to calculate future outcomes.
The principle is simple: if user moves the task closer to release (e.g. from In Progress to Done), his karma increases. If moves tasks back (e.g. from Done to Reopen), then previous user will have his karma lowered.
User Karma can be overriden manually on the user profile page. It can be done by admins (though they can't change their own karma). But it's better to let plugin do its job calculating karma automatically, just configure Transitions Karma.
Issue Risks vs. Issue Karma
Issue Karma is similar to User Karma in a sense that if issue gets closer to release, its karma increases and if it moves backward, its karma goes down.
Issue Risks is a bit different beast. Risk in general equals 1-karma. Issue Risks in particular are calculated from karma of the users who was working on this issue. The higher the karma of those users, the lower the risks and vice versa.
Transitions Karma is configured by admins - these are the metrics by means of which Pugin decides whether the issue moved further to or from release. Provided that you're an admin, you must see Karma menu item at the top of JIRA UI. This is the best starting point to begin working with Karma Plugin.