The following four types of issue dependencies are available:
This is the most common and logical type of dependency in project management and the real world. In this scenario, the predecessor task must finish before the successor can start.
It follows the natural flow and progression from one task to another. Task A must finish in order for Task B to start.
This dependency means that if there are 2 tasks TASK A and B, the dependent task (B) cannot begin until the task that it depends (A) on is complete. In other words, if TASK A is delayed by a day, then B will also be delayed and will begin a day later.
The “Start-to-Start” dependency says that a task cannot start before the predecessor task starts. This dependency means that if there are 2 tasks TASK A and B, Task B can’t start until Task A starts. They don’t have to start at the same time: Task B can begin any time after Task A begins.
In this case, a task cannot end before the predecessor task ends. This dependency means that if there are 2 tasks TASK A and B, Task B can’t finish until Task A is completed. They don’t have to end at the same time: Task B can end anytime after Task A ends.
One peculiar dependency, which is rarely used, is “start to finish”. In this case, the predecessor task must start before the successor task can finish. Task B can’t finish until Task A begins. Task B can finish any time after Task A begins. This type of link is rarely used.
As a rule of thumb, a good practice is to stick with the common “Finish-to-Start” dependency or else you run into the risk of creating a gantt chart confusing others.
Suggestions and Auto-Balancing
If you have enabled “Suggestions” within your Jira project administration and also enabled the option “Auto-Balancing” then all your issues without having explicitly set planning dates will be scheduled as a sequence of task per assignee: this is the same as if they would be linked to each other by an (implicit) “Finish-to-Start” dependency. Doing this, tasks will not overlap and avoid overloaded workloads. This can only occurs in combination with explicitly set planning dates, but will be displayed on screen if you select the “Resource View”.