One of the most common tasks is to schedule a series of events, and the complexity of this task can vary considerably depending on how the tool is used. Some common challenges include:

• Events which depend on one another in different ways or dependencies.
• Scheduling people to work on, and resources required by, the various tasks commonly termed resource scheduling.
• Dealing with uncertainties in the estimates of the duration of each task.

B. Calculating critical path

In many complex schedules, there will be a critical path, or series of events that depend on each other, and whose durations directly determine the length of the whole project. Some software applications can highlight these tasks, which are often a good candidate for any optimization effort.

C. Providing information

Project planning software needs to provide a lot of information to various people, to justify the time spent using it. Typical requirements might include:

• Tasks lists for people, and allocation schedules for resources.
• Overview information on how long tasks will take to complete.
• Early warning of any risks to the project.
• Information on workload, for planning holidays.
• Evidence.
• Historical information on how projects have progressed, and in particular, how actual and planned performance are related.
• Optimum utilization of available resource.
  

Project management software can be implemented as a Web application, accessed through an intranet or extranet using a web browser.

This has all the usual advantages and disadvantages of web applications:

• Can be accessed from any type of computer without installing software.
• Ease of access-control.
• Naturally multi-user.
• Only one software version and installation to maintain.