Actual Work: Hours collected in a timesheet or with a timer indicating the total project hours an employee has actually worked.
Collecting actual work in a product like Standard Time® in important. It allows you to compare your original forecasts with the actual hours worked by employees. This can lead to some valuable metrics, including percent complete and estimation variance.
Assuming your original estimates are close, percent complete will tell you how far along the project is. This is obviously more valuable to project managers and executives who are slightly distanced from the day to day tasks. In some cases this can be their only indicator of the project status.
Refining your estimations can also be valuable, especially if your company performs the same projects over and over again. Only actual work can give you exact numbers, and that can lead to more profits.