When working with tasks in a project, it is common practice to display a duration as an estimate. Displaying an estimated duration prepares the viewer for possible changes in scheduling. An estimated duration takes the form of a question mark placed after the declared duration.
The issue is that some project viewers fail to notice the question mark; then when durations are updated, project viewers wonder why things have changed. One way to ensure that people’s attention is drawn to the estimated durations is to change the color of the Gantt bars to reflect an estimated status. There is no built-in state for displaying estimated durations in a separate color, but with a few short clicks this behavior can be achieved.