Hierarchical Calculated Field
Hierarchical Calculated Field is an app for Jira - developed by mgm technology partners, Which enables you to create the new custom field type "Hierarchical Calculated Field".
This app provides the possibility to sum up values from other referenced fields and roll up the result from the lowest hierarchy level (Sub-task) to the highest hierarchy level (Epic).
You can define the deep of the hierarchy levels by choosing the reference issue. This could be sub-tasks → parent-task, sub-tasks → linked-issues→ parent-task, sub-task → issues in epic → epic or sub-tasks → stories in epic → epic.
Including sub-tasks in 3 level hierarchies is optional.
Different statistics, for example sum, average, maximum or minimum are available to evaluate the value of all HCF in your hierarchy tree.
Use this app to make a bottom-up estimation for the project schedule. Make accurate estimates at a detailed level and put the sum of these estimates to the story or epic.