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. 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.
How to Add a Dependency in the Schedule
To establish a dependency in the Schedule, just connect a line between the start or end dates of the predecessor and successor task bars.
- First, 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 End date.
- Keeping in mind the type of dependency you want to establish, hover over the circle until it turns grey and your cursor becomes a pointer.
- Now, click and drag. You'll notice that circles appear at the beginning and end of all other task bars.
- Continue dragging the dotted line to a circle on your successor task (either the Start date on the left, or the End date on the right) and then release.
- The dependency is formed, represented by a black arrow that points from the predecessor to the successor.
How to Add a Dependency in the Tasks List
When establishing dependencies from the Task 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.
- In the Predecessors column, double-click on the successor task for which you’re establishing the dependency.
- 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).
- Your new dependency will be shown in the Schedule as a black arrow pointing from the predecessor to the successor.
How to Change a Dependency Type in the Schedule
- In the Schedule, double-click on the black dependency arrow that connects a predecessor to a successor to change the Type.
How to Change a Dependency in the Tasks List
- To change the dependency from the Tasks list, double-click on the successor task and type the line # of the predecessor task (e.g.
4), followed by the initialism for your new dependency type (finish to start=FS, start to start=SS, finish to finish=FF, and start to finish=SF).
How to Delete a Dependency in the Schedule
- Double-click on the black dependency arrow in the Schedule.
- Click Delete.
How to Delete a Dependency in the Tasks List
- Right-click on a known dependency in the Tasks list.
- Hover over the Delete dependency... option.
- If there is more than one dependency, select the one that you want to delete.
By default, the Cascade button, just above the Schedule in the timeline header, is always enabled when you open the Local Gantt chart.
When Cascade is active, 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:
- If Cascade is enabled when you establish a dependency, the Start and End dates of the successor are automatically shifted in relation to the Start and End 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.
- If Cascade is enabled when you're editing dates, changes will automatically roll down to all dependent tasks on the Schedule.
- If you establish dependencies or modify dates with Cascade disabled, all tasks move independently of one another on the Schedule.
Regardless of whether Cascade is enabled, adjusting Start and/or End dates does not delete the dependency or change it's type.
Setting Lag and Lead
If Cascade is enabled 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. Alternately, you can create a lead wherein the successor task starts before the predecessor task ends.
How to Add a Lag or Lead
- Make sure that Cascade is enabled.
- In the Schedule, double-click on the black arrow indicating the dependency for which you want to set a lag or lead.
- To create a lead—set your Lag to a negative number; to create a lag—set it to a positive number of days.
- Click OK.
WHAT THE MAVENS KNOW
Dependency relations are established in the Local Gantt chart, so it's best to make date modifications here. Although you can modify task dates in the Task Tracker, the ability to cascade changes to dependent tasks is not enabled by default. Click here for information on how to cascade changes to dependencies using the project Task Tracker.
- Gantt Chart Overview