Software Engineering Blog | Software engineering , Software Document ,Software Process: How to Build " Gantt Chart" Step by Step

Tasks are activities that must be completed to achieve the project goal. Break the project into small tasks and subtasks. Tasks have start and end points, are short relative to the project and are significant (not "going to library", but rather, "search literature"). Shorter tasks are easier to track and manage than long tasks. For our 14 week project, no individual task should be longer than one week. Use verb-noun form for naming tasks, e.g. "create drawings" or "build prototype". Use action verbs such as "create", "define" and "gather" rather than "will be made". Each task has a time duration. It can be very difficult to estimate
durations accurately. Doubling your best guess usually works well. Allow some contingency time for unexpected events (10-25%).

Table 1 Example of website development task

Milestones are important checkpoints or interim goals for a project. They can be used to catch scheduling problems early. Name by noun-verb form, e.g. "report due", "parts ordered", "prototype complete". Your plan will evolve so be flexible and update on a regular basis. It also helps to identify risk areas for project, for example, things you don't know how to do but will have to learn. These are risky because you may not have a good sense for how long the task will take. Or, you may not know how long it will take to receive
components you purchased for a project.

To draw up a Gantt chart, it must follow these steps:

Step 1 - List all activities in the plan. For each task, show the earliest start date, estimated length of time it will take, and whether it is parallel or sequential. If tasks are sequential, show which stages they depend on.

Step 2 - Head up graph paper with the days or weeks through to task completion.

Step 3 - Plot the tasks onto the graph paper. Next draw up a rough draft of the Gantt Chart. Plot each task on the graph paper, showing it starting on the earliest possible date. Draw it as a bar, with the length of the bar being the length of the task. Above the task bars, mark the time taken to complete them.

Step 4 - Schedule activities. Now take the draft Gantt Chart, and use it to schedule actions. Schedule them in such a way that sequential actions are carried out in the required sequence. Ensure that dependent activities do not start until the activities they depend on have been completed. While scheduling, ensure that you make best use of the resources you have available, and do not over-commit resource.

Step 5 - Presenting the analysis. The final stage in this process is to prepare a final version of the Gantt Chart. This should combine the draft analysis (see above) with your scheduling and analysis of resources. This chart will show when you anticipate that jobs should start and finish. In constructing a Gantt chart, keep the tasks to a manageable number (no more than 15 or 20) so that the chart fits on a single page. More complex projects may require subordinate charts which detail the timing of all the subtasks which make up one of the main tasks. For team projects, it often helps to have an additional column containing numbers or initials which identify which one in the team is responsible for that task6.