The rating for SCED is defined in terms of the percentage of schedule stretch-out or acceleration with respect to a nominal schedule for a project requiring a given amount of effort. The following table delineates that accelerated schedules produces more effort in initializing phases in order to eliminate risks and refine the architecture, but more effort in concluding processes to achieve more system tests and documentation. Stretch-outs in schedule are not considered as adding to or decreasing the effort in developing software.
| SCED Descriptors | 75% of nominal | 85% of nominal | 100% of nominal | 130% of nominal | 160% of nominal | |
|---|---|---|---|---|---|---|
| Rating Levels | Very Low | Low | Nominal | High | Very High | Extra High |
| Value | 1.43 | 1.14 | 1.00 | 1.00 | 1.00 | n/a |