Slippage tracks the tasks that haven't started yet. It is the difference between the baseline start date and the current start date of the task. Baseline start date is the original start date of the task.

1. Navigate to a project and then select Gantt & Reports > Milestone Gantt.
2. Click   in the upper right corner.
3. Select Slippage to calculate the slippage of a baseline.
   • Slippage is the dark gray line from the baseline start date to the current start date.