Gantt Chart Dependencies

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Overview

In the Local Gantt chart, dependencies allow you to define relationships between tasks and visualize the sequence in which they must be completed in order to close a project.

There are two steps to creating a dependency—first, identify the predecessor and successor tasks and then establish a relationship between them.

By definition, the predecessor is the first task; it controls the start or end date for all related successor tasks. The successor, by contrast, is the task whose start or end date is controlled by the predecessor.

A dependency is the relationship between predecessor and successor tasks. Tasks may have multiple predecessors or multiple successors.

Note: You are not allowed to create circular dependencies. If you experience errors due to circular dependencies, see Task Dependencies in Task Tracker to learn how they can be resolved.

Before you begin establishing dependencies, it’s important to understand that there are four types:

• Finish to Start (FS)—The predecessor ends before the successor can begin.
• Start to Start (SS)—The predecessor begins before the successor can begin.
• Finish to Finish (FF)—The predecessor ends before the successor can end.
• Start to Finish (SF)—The predecessor begins before the successor can end.

Dependencies can be managed from the Local Gantt in both the Tasks list and the Schedule.

Note: You are not allowed to create circular dependencies. If you experience errors due to circular dependencies, see Task Dependencies in Task Tracker to learn how they can be resolved.

How to Add a Dependency in the Schedule

1. Hover over Projects in the left navigation, and select your project. 
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Schedule section on the right side of the screen, hover over the predecessor task bar until a circle appears at either edge. The left circle represents the task’s Start date, and the circle on the right represents its Finish date.
   
4. Hover over the circle until it turns gray and your cursor becomes a pointer.
   
5. Click and drag. You'll notice that circles appear at the beginning and end of a different task bar when you hover over it.
   Note: As you hover over areas where a dependency can't be created, you'll see a red Invalid message. Once you hover over areas where it can be created, this changes to a green Valid message.
6. Continue dragging the dotted line to a circle on your successor task (either the Start date on the left, or the Finish date on the right) and then release.
7. The dependency is created, represented by a gray arrow that points from the predecessor to the successor.

How to Add a Dependency in the Tasks List

When establishing dependencies from the Tasks list, you must add a predecessor from the successor task. In other words, you begin with the successor and then add a predecessor to it.

1. Hover over Projects in the left navigation, and select your project. 
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Predecessors column, double-click on the successor task for which you’re establishing the dependency.
4. Type the line # of the predecessor task (e.g. 5), followed by the initialism for the type of dependency that you’re establishing (finish to start=FS, start to start=SS, finish to finish=FF, and start to finish=SF).
   Note: You can also click the drop-down arrow on the right side, select the predecessor task, and then indicate the type from the menu that appears.
5. Your new dependency appears in the Schedule as a gray arrow pointing from the predecessor to the successor.
   

How to Change a Dependency Type in the Schedule

1. Hover over Projects in the left navigation, and select your project. 
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Schedule, double-click the dependency task you want to change the type for. The Information modal opens.
4. Select either the Predecessors or Successors tab.
5. In-line with the specific dependency, select a new option from the Type drop-down.
   
6. Click Save.

How to Delete a Dependency in the Schedule

1. Hover over Projects in the left navigation, and select your project.
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Schedule, double-click the dependency task you want to change the type for. The Information modal opens.
4. Under the Successors tab, click the Delete (“   ”) icon in the bottom-left corner.
   Note: If there is more than one dependency under the Successors tab, select the one you want to delete.
5. Click Save. 

How to Delete a Dependency in the Tasks List

1. Hover over Projects in the left navigation, and select your project.
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Tasks list on the left, double-click the Predecessors column in-line with the specific task, and then delete the value.
4. Double-click the Successors column, and then delete the value.

Cascade Dependencies 

With the Gantt chart’s cascade dependencies functionality, any time you establish a dependency or modify a Start and/or Finish date, changes automatically roll down to dependent tasks so you don’t have to manually change the dates of all successors.

Here’s how it works:

• When you establish a dependency, the Start and Finish dates of the successor automatically shift in relation to the Start and Finish dates of the predecessor. For example, if you’re establishing a Start to Finish dependency, the successor task begins directly after the predecessor task ends.
• When you edit dates, changes automatically roll down to all dependent tasks on the Schedule.

Note: Adjusting Start and/or Finish dates does not delete the dependency or change its type.

Known Issue

When a parent task has subtasks with dependencies, shifting the parent’s predecessor will cause the subtasks to be realigned to all start on the same day. The dependency of the subtasks will not be respected.

To avoid this issue, connect the predecessor task to the first subtask instead of the parent task. Then when you shift the predecessor, the dependency will be respected, and the parent task will automatically recalculate based on the dates of the subtasks.

Setting Lag and Lead

When you establish a dependency, the default delay between predecessor and successor is one day. For instance, with a Finish to Start dependency, the succeeding task will begin on the day after the preceding task ends. You can extend the days between the predecessor and successor tasks by setting a lag. Alternatively, you can create a lead wherein the successor task starts before the predecessor task ends.

How to Add a Lag or Lead

1. Hover over Projects in the left navigation, and select your project.
2. In the project workspace, click the Gantt tab. The Local Gantt chart opens.
3. In the Schedule section, double-click the dependency task for which you want to set a lag or lead. The Information modal opens. 
4. Select either the Predecessors or Successors tab.
5. In the Lag column, click the up or down arrow to specify the amount of lag or lead days, or manually type in the amount.
   Note: To create a lead, set your Lag to a negative number. To create a lag, set it to a positive number of days.
   
6. Click Save. 

Related Articles

• Gantt Chart Overview
  • Global Gantt Chart Basics
  • Tasks Gantt Chart Basics
  • Local Gantt Chart Basics
    • Manage Tasks in Gantt Charts
    • Create and Manage Dependencies
• Save a Baseline in Gantt Charts
• Export a Gantt Chart