As the diagram below shows, we are looking at a network diagram with logical relationships. While the PMBOK® Guide puts an emphasis on performing the precedence relationship shown below, manually, there are a number of automated tools such as Primavera and Microsoft Project that enable the creation of precedence diagrams easily.
How necessary are these tools? If the project plan is only 20 or 30 lines you can probably get away with using Microsoft Excel as a project planning tool. If the project plan is a few hundred to several thousand lines (for example, a project plan of several hundred thousand lines might require a Primavera Master Scheduler), you may need a software tool to keep track of project elements.
Creating a diagram like the one shown above in Microsoft Project might take the user a weekend’s worth of preparation, but it is well worth the effort. This is useful for a construction project or a project similar to a construction project where the product is fundamentally plan driven. For agile or adaptive projects, it is recommended that an adaptive tool is used such as VersionOne.
In either case, it will take a few days of instruction or about a week’s worth of individual effort to get up to speed tool like Microsoft Project or VersionOne.
This is an excerpt from the Global Knowledge white paper, Are All Those Project Management Tools Really Needed?