In Jira Software, we have three levels of issue types: Epic Base Sub-task While Epic is a generic term that simply act as a container to put Base items in, we use that in the Flexible Atlassian Setup as a representation of a Feature. This means that an Epic will contain items that need to be done to deliver a functional feature in this setup. The Base items are the actual work orders that we use to fulfill a requirement. Sub-tasks are breakdowns of activities the assigned person to a Base item feel is necessary to complete the work. The sub-tasks are completely optional, and they should never be work orders themselves. This means that all sub-tasks should belong to the same person that own the Base item. If there is need to divide the work in a Base item, then that Base item should be split into two rather than having multiple sub-tasks assigned to different persons.
