What is the difference between standard issue type and sub-task issue type

[Kimi Nakashima]

I'm a Jira newbie and playing around in our test project to learn. When I went to create a new issue type I noticed that in addition to Name and Description you get a choice of type; standard issue type and sub-task issue type. I couldn't find much in the documentation or in the community about the differences between the 2 types of issue types and when you should use them.

[Stephen Crandell]

The difference between the two is related to the size of work being done and the relationship the issue type will have to other issues. Stand issue types defines a unit of work, whether that be a task, story, epic, bug, etc. A sub-task issue type is a defined as just a piece of a larger unit of work. For example, say you have a story to develop an engine, the overall goal is create a working engine. However, there are many pieces to any working engine. You could have individual subtasks to develop the components of the engine like a transmission subtask, alternator subtask, carburetor subtask, etc.

The software development world is no different. You could have a Story to develop a new feature for an existing application. To get that feature released you could have individual pieces of the development, deployment, testing, and release as subtasks. Each is a smaller piece of work to a larger overall application.

In Jira, subtask have a specific link to a parent (standard issue type). This affects how you create a subtask. In your test project you are playing around with, when you create a new issue, the only options you have are the standard issue types. To be able to create a subtask issue, you MUST have a parent record and create the subtask issue "under" that parent issue. 

Hope this helps!

[ChristopherChilds]

Hi @mrcrandell.sw and @Deepanshu Natani 

great detailed answers. I am still at a loss about why they are not just a Standard Issue Type which can be created against a Story, a Task or an Epic or any other including custom Issue Types.
There are some special features which I do find annoying because they do not obey the rules of other issue types like they hang around on a sprint board like a bad smell till the parent issue type is closed.

There are a few other issues I have seen where for the average user it causes a little confusion when making configuration or Automation rule changes etc.

[Deepanshu Natani]

Hi @Kimi Nakashima

A task is a normal standalone issue type in Jira.

Sub-tasks are tasks that have a parent issue.

In case an issue/ task is too big and complex then the issue/task can be broken down into logical sub-issues known as ‘Sub-tasks’ in Jira. These smaller issues can then be managed more efficiently.

Each sub-task can be worked upon by a separate person, which in turn allows monitoring the progress of the main task in a better way.

Once sub-tasks are created, the main issue is referred to as the parent issue.

In conclusion Task is an independent issue type while a Sub-task needs a parent issue.