Gantt charts provide a standard format for displaying project schedule information by listing project activities and their corresponding start and finish dates in a calendar format.
Symbols include:

-A black diamond: milestones or significant events on a project with zero duration
-Thick black bars: summary tasks
-Lighter horizontal bars: tasks
-Arrows: dependencies between tasks

Producing a Gantt chart
All scheduling information is graphically represented in a Gantt chart:

-tasks (with name)
-task durations
-relation of task dates to calendar time
-relation of task dates to each other

Constructing a Gantt chart
Draw two axes:

– x-axis: time (days/weeks/months, etc.)
– y-axis: tasks

Label the axes appropriately with calendar dates (x-axis) and task names or WBS numbers (y-axis)
For all tasks:

-draw a horizontal bar, representing the task, at the appropriate (x,y) position (i.e. at
calendar start date in the task’s row)
-make the bar as long as the task’s duration (according to the time axis)
-proceed from the earliest to the latest task

Benefits of Gantt Charts
The Gantt chart is the project manager’s most important tool:

– it provides an overview of the whole project
– the schedule of all tasks can be easily seen
– task relationships/overlaps can be easily seen
– progress can be tracked easily

– Simplest form of schedule to read and interpret

– Easy to create

– Readily communicates results of a network diagram

– Repetitious schedules in bar chart format require far less maintenance than CPM schedules

Disadvantages of Gantt Chart

•Cannot depict intricacies of multiple activity interaction (relationships not shown)
•Simplicity reduces effectiveness and accuracy on large projects with many tasks
•Accuracy is limited because task interdependencies are not tracked
•Too easy to create, thus can produce unrealistic schedules
•Too easy to start from end date, and spread out bars to fit time allotted with
unrealistic sequences, constraints, and durations
•Scheduler’s design logic (relationships) is not readily apparent, thus tracking change impact is difficult