Data Type Duration (duration field: A type of field whose content is expressed as a duration of time. Examples include the Work, Duration, and Delay fields. A duration field includes the duration unit, such as hour, day, or week.)
Entry Type Calculated (calculated field: A field in which the value is determined by Project based on information in other fields. Project may recalculate the value automatically or when you specify, depending on your choice of calculation settings.)
Description The Negative Slack field shows the amount of negative slack for a task on the Gantt Chart, indicating the amount of time that must be saved so that successor tasks are not delayed. Negative slack indicates that there is not enough time scheduled for the task and is usually caused by constraint dates or task dependencies. This field is available only in the Bar Styles dialog box and is represented as a bar on the Gantt Chart.
How Calculated When you use the Negative Slack field on a Gantt bar, Project displays a graphical representation of a task's negative slack value based on the value in the Total Slack field. Total slack is calculated as the smaller value of the Late Finish field minus the Early Finish field, and the Late Start field minus the Early Start field. If total slack is a negative number, there is negative slack. Therefore, on the Gantt Chart, negative slack indicates the date by which a task must be started to prevent successor tasks from being delayed.
Best Uses Add the Negative Slack field as a Gantt bar style when you want to indicate graphically on the Gantt Chart the amount of negative slack for tasks.
Example You want to view graphically how much time needs to be recovered in your schedule for various tasks. You add the Negative Slack field to the Gantt Chart. You add a Gantt bar that displays the amount of negative slack to the start date.
Remarks You can set the negative slack bar on the Gantt Chart in the Bar Styles dialog box.