From the course: Project Management Foundations

Put tasks in sequence

From the course: Project Management Foundations

Put tasks in sequence

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- [Instructor] A big part of building a schedule is getting tasks in the right order. Mealtime goes a lot better when you cook dinner before you eat it. By putting tasks in order, you turn your WBS into a sequence that defines when project work should occur. In the project management world, network diagram is the name for the diagram that shows the sequence of tasks. Each task appears in a box with the task name and perhaps other task info. Arrows drawn between boxes shows how the tasks are linked. Even if you build the sequence by putting sticky notes up on a whiteboard, you're creating a network diagram. The links between tasks aren't just about which task starts first. A task dependency is when one task controls the timing of another. The task in control is called a predecessor, and the one being controlled is the successor. Each task has a start and finish. So there are four types of task dependencies. Finish-to-Start dependencies are the most common. The finish of one task controls when the other task start. For example, you have to analyze the current scheduling processes before you can start designing new ones. A Finish-to-Finish dependency means the finish of one task controls the finish of the other. For example, the dev team finishing the scheduling features controls when they finish testing the features with a small delay to test those last bits of customization. Start-to-Start means that the start of one activity triggers the start of the other. This dependency type can cause trouble if the predecessor takes longer than it's supposed to as shown here. If writing takes longer, the reviewing task looks like it finishes before writing does. That would mean either some writing isn't reviewed or the reviewers have to wait until the writing is done. In this example, the correct logic is actually Finish-to-Finish. With a Finish-to-Finish dependency, if the writing finish date is delayed, so is the finish date for reviewing. An example of a true Start-to-Start dependency is pouring concrete and troweling it. Because concrete hardens with time, the start of pouring concrete controls when troweling starts. Start-to-Finish dependencies don't occur very often. That's a good thing because they can be confusing. The start of one task triggers the finish of another, so the task can control occurs after the one it controls. Consider the shifts at a retail store. The first shift can't finish until the clerk for the second shift shows up. You can figure out which type of dependency to use by asking a few questions. Which task controls the other? That tells you which task is the predecessor. Does the start or finish date of the first task control the second task? That identifies whether the dependency begins with start or finish. Does the predecessor control the start or finish of the successor? That identifies whether the second half of the dependency is start or finish. Adding task dependencies to your tasks in a network diagram, gets your project tasks into sequence. Now that you know all the dependency types, build a network diagram for the tasks in the partial WBS in the exercise files.

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