Data Type Percentage (percentage field: A type of field whose content is a percentage. Examples include the %Complete and %WorkComplete fields.)
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 Cumulative Percent Complete field shows cumulative percent complete (percent complete: A field that you use to enter or display how much of a task has been completed. This value is expressed as the percentage of the task duration that has been completed.) values for a task as distributed over time.
How Calculated When a task is first created, the cumulative percent complete is zero. As soon as you enter a percent complete for the task or enter actual duration, remaining duration, or actual work so that Project can calculate percent complete, Project also calculates cumulative percent complete either to the status date or to the end of the actual duration on the task.
Best Uses Add the Cumulative Percent Complete field to the timephased portion of the Task Usage view when you want to display the timephased cumulative percent complete values. You can use this field to review the percent complete progress of a task over its duration (duration: The total span of active working time that is required to complete a task. This is generally the amount of working time from the start to finish of a task, as defined by the project and resource calendar.), as reported with actual (actual: Information that shows what has actually occurred. For example, the actual start date for a task is the day that the task actually started.) duration, remaining duration, or percent complete.
Example You want to see the point at which the "Write proposal" task changed from 25 percent to 50 percent complete. You add the Cumulative Percent Complete field to the Task Usage view and review the values in the time periods for this task. On Monday when the task started, the cumulative percent was zero. On Tuesday and Wednesday, it was 25 percent. On Thursday, it changed to 50 percent.
Remarks You can control whether edits to total percent complete are distributed through the status date or to the end of the actual duration on the task. This affects your earned value results. But most importantly, if you use progress lines, it allows the lines to show ahead of schedule progress. You can do this in the Project Options dialog box.