Themes

• A Theme is a key objective or goal which could be across projects and products. Themes can be broken down into sub-themes, which are more likely to be product-specific. At its most granular form, a Theme may be an Epic.
• Themes can be used at both Programme and Project Level to drive strategic alignment and communicate a clear objective or goal.

EPICS

• An Epic is a grouping of User Stories that can be logically grouped. Epics are broken down into user stories to detail them out.
• Epics can be used at a both Programme and Project Level.

User Stories

• An User story is an Independent, Small, Testable requirement that has clear acceptance criteria and estimate.
• User Stories are great for Project and Product Development Teams as they are easy to understand, discuss and prioritise – they are prioritised in a product backlog and become part of Sprint as deliverables. 

Tasks

The project / product team members break up the User Stories into smaller Tasks during the Sprint Planning Process to achieve the user story functionality. User stories that are too small may not have a need to break up in tasks.