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A bit of planning

Posted on 11 May 2007 at 11:47

Ian Wrigley and Simon Brock look at some open-source project planning and management applications to scrutinise their capabilities in the real world.

After this lengthy disclaimer, we can't avoid explaining that there are two main types of diagram used in project planning, the Gantt chart and the PERT chart. The Gantt chart was the earliest formal planning methodology and dates back to the early part of the 20th century: it attempts to break down the total work involved in achieving a project into a structure that can be understood by the people involved in executing the project. The model is hierarchical, showing visually how each task depends on others, and it also shows how the deliverable outcome of one task can be fed into another task so these dependencies can be seen clearly. The Gantt structure isn't perfect, because it can't represent all the properties of a plan you might need, but it's approachable and easy to draw.

The Program Evaluation and Review Technique (PERT) chart, developed in the 1950s, represents a later approach to project-planning diagrams. It has similar goals to the Gantt chart, but its representation is more complete and more open to various forms of analysis, making it both more complex to draw and to understand. A particular advantage of the PERT chart is that it makes it very easy to see the "critical path";that is, the crucial sequence of tasks in a project in which any delay can't be absorbed and must cause the end date of the project to be put back.

Most people tend to start with Gantt charts, so we're going to look first at an application called GanttProject, which can be downloaded from http://ganttproject.biz. GanttProject is a Java application and as such runs on virtually every computing platform there is. There are installers for Windows, Mac OS X and Linux, but you may need to download a Java virtual machine as well if you don't have one already installed.

A Gantt chart links two types of information: tasks and resources - tasks being the jobs that need to be done and resources being the people who are going to perform these jobs. Tasks can be split up in hierarchical fashion so that each task is made up of smaller tasks, and it's possible to link tasks to show their dependencies. When you first launch GanttProject, you'll be presented with an empty plan onto which you enter the tasks, and once you've laid out your plan as a collection of tasks you can start allocating people (or rather "resources") to them. GanttProject understands that people don't generally work on bank holidays and weekends, as well as allowing you to enter the days they're on holiday.

Having arrived at your tasks and allocated your resources, you're well on the way to producing a plan. GanttProject's interface is very easy to use, allowing tasks to be changed by dragging and dropping, and you can set the progress in each task to show how your plan is developing as people tell you how far they are through their tasks. GanttProject makes the process of setting up and maintaining a plan reasonably painless, but it does have some features missing. For example, it allows you to allocate people to project tasks even when they're on holiday, without receiving any kind of warning - you only see it on the resource allocation page for the project. While this is a weakness of the product compared with its more complex commercial competitors, it isn't a total show-stopper, but it does mean you have to be more careful about how you evaluate your plan. The application also supports the automatic creation of PERT charts from your Gantt charts, which can be useful for evaluating critical paths and is sometimes a preferable way of presenting a plan.