A production method where the final product and completion date set the schedule working backwards to today. The schedule is then broken into tasks in the order they must be completed. This is a method for revealing all milestones and setting reasonable expectations for each. As the schedule is built, milestones can be individually judged for time and priority without adjusting the final deadline date.
The completion date can be adjusted, but only after recognizing what needs to be done to create the final product.
In a software or web project the common structure of a workback spreadsheet might include columns such as major task, sub-tasks, start date, end date, total estimated hours, current status, and assigned to. The final row will start the spreadsheet with the final product and completion date.