The Architecture of Time, Part 3: Project Management in Two-Dimensional Time

The Gantt chart depicts the current prediction of how the future is going to unfold, but it does not adequately tell the history of the project’s efforts to get to that future. This is because the Gantt chart is really a series of charts, each of which has only one dimension— time—running from left to right across the page. The vertical dimension does not signify a continuum, but is simply a means of compiling the schedule of individual albeit interdependent milestones onto one visual display. It is today's snapshot of how those milestones relate to each other in the overall schedule, but it does not show very well how those milestones have influenced each other over time. It would be valuable to have some way of displaying all of yesterday's schedule snapshots as well as today's on a single chart. Then one could see at a glance the nature of the trends for each milestone and how they feed into the trend of the master schedule. This can be done by reformatting the chart so that a second dimension of time is displayed. The time axis on a conventional schedule chart isn't real time in the sense of showing the occurrence of actual events with respect to the passage of time; it is only projected time—the pseudo-temporal axis along which a manager positions his best guesses of when he will achieve his milestones. In a chart that not only contains the pseudo-temporal axis but also a second axis corresponding to the actual passage of time, one can see the history of a program's perception of the future—how schedules have been influenced by the course of events, and how they have evolved with time. Presentation of schedules in this new two-dimensional format provides managers an extra dimension of information, enabling them to make better subjective judgments on how realistic the current schedule is, and how it may change in the face of possible future events.