After you build your project schedule and add associated tasks, you can set up relationships between the tasks. These relationships are also known as dependencies.
You can structure dependencies logically, such that certain tasks rely on the start or completion of other tasks before they can be accomplished. Establishing task dependencies makes it possible to keep close track of your project's critical path and overall schedule and to identify potential schedule risks.
Schedule Tab of Project Planning
Use the Schedule tab of Project Planning to set up dependencies between tasks. This tab provides an interactive Gantt chart that displays a timeline for each task on your project's Work Breakdown Structure (WBS). This provides a quick way to see, and work with, the project schedule, tasks, relationships between the tasks, and critical path.
Predecessor and Successor Tasks
When you create a task dependency, you must consider the WBS structure and the type of relationship that you want to create between tasks, including which task is the predecessor and which task is the successor:
- Predecessor — The predecessor task determines when another task will start or finish based on the established relationship.
- Successor — The successor task's start or finish date is determined by a relationship established with another task.
The most common relationship is when the predecessor task's finish date determines the successor task's start date. This, along with the other relationships that you can establish between tasks, is detailed below in the Types of Dependency Relationships section.
You can only create dependent relationships for items that are at the
lowest level of the Work Breakdown Structure (WBS). These are the lowest child-level, or lowest leaf nodes, of the WBS. They display under a parent level but have no WBS children of their own. For the purpose of task dependencies, these are referred to as "tasks" but they may be phases, tasks, labor codes, or lower indent levels, depending on the WBS structure.
Types of Dependency Relationships
Vision supports four types of task dependency relationships:
- Finish to Start — The successor task cannot begin until the predecessor task is complete. This is the most common relationship used when planning projects. You can also use the right-click shortcut menu to select
Set FS Relationship to build this type of relationship between two or more tasks.
- Start to Start — The successor task cannot begin until the predecessor task begins.
- Finish to Finish — The successor task cannot be completed until the predecessor task is completed.
- Start to Finish — The successor task cannot be completed until the predecessor task has begun.
You can create dependent relationships between tasks on the Schedule tab by using any of the following methods:
-
Edit Dependency Dialog Box — To display this dialog box, double-click a task bar, or right-click a task bar to open the shortcut menu and then select
Edit Dependency. Select the predecessor task and then use the
Relationship field to select a relationship for the predecessor and successor tasks. You can also enter the number of days and specify the direction for defining the lag or lead time for the dependency.
- — Select two or more tasks, right-click to open the shortcut menu, and select
Set FS Relationship. The first task selected will be the predecessor and all subsequent tasks selected will be the successors, with a Finish to Start relationship applied.
In each of these cases, an arrow from the predecessor to the successor displays between the tasks. If you change the dates for a predecessor task, all successor tasks change accordingly. Updates on the Schedule tab automatically update corresponding information on the Labor, Expense, Consultant, and Unit Planning tabs.
Task Dates
The
Start and
Finish dates of the parent WBS level that displays on the Planning tabs can begin earlier than the earliest start date of its child WBS level task or end later than the latest end date of the last child WBS level task. However, when using the Schedule tab of Project Planning to schedule task dependencies, the parent WBS start and end dates
must align with the start and end dates of the child WBS level tasks. If there is a discrepancy, Vision requires that you collapse the parent start and end dates on the Planning tabs before you can use the Schedule tab. Collapsing the dates means that the parent WBS level start and/or end dates will be adjusted to match the start and/or end of the child dates.
Dependent Task Indicator on the Labor Tab
After task dependencies are created on the Schedule tab, the Labor tab of Project Planning displays a
in the Dependency column on the task row to indicate that the task has a dependent relationship. You can right-click the row and select
Dependencies to open a dialog box that displays the dependent predecessor or successor tasks for the current row. Refer to this information when building task dependencies or before changing dates for one or more task rows.
Your system administrator configures the
Dependency column to display in
.