Gantt Chart

What it shows

Tasks run down the side, the calendar runs across, and each task gets a bar from start to finish. Arrows between bars are dependencies; diamonds are milestones. Summary tasks with children are usually drawn as a bar spanning all their descendants, while leaf tasks — where the actual work happens — get individual bars. Put it next to the WBS tree and "what we do" and "when we do it" share one screen.

Why it matters

It is the shared language of schedule conversations. "If that task slips, what happens downstream?" — spoken in meetings, answered visually by moving bars and arrows. A Gantt chart drawn on top of dependency logic lets you trace the ripple of a delay with your eyes, and a highlighted critical path shows which bars must be defended first. In client reporting too, bars read faster than tables of numbers.

Using it well

Three switches multiply the information on screen. First, critical-path highlighting: the bars that must not slip stand out by color. Second, baseline overlay: the drift between the approved plan and the current plan shows as a reference line beside each bar. Third, a today line: a bar left of today with progress unfilled is a delay candidate. One caution — a bar's length is duration, not effort. A long bar is not necessarily a big job.

Common misconceptions

Drawing a Gantt chart and building a schedule model are different things. A Gantt made of colored spreadsheet cells is a picture: when a predecessor slips, the downstream bars do not move by themselves. A living Gantt needs a model behind it that computes dates from dependencies and durations. Wiring the logic correctly comes before making the bars pretty.