The technical requirements need to be sufficiently detailed to assure that firm schedule estimates can be established. The schedule needs to show the major development activities throughout the life cycle, the milestones, and a critical path. See SWE-016 Software Schedule for in-depth information on the general preparation of software development schedules.
To be effective, the software supplier schedule needs to have linkage to the project schedules, if the two are different. The suppler schedule can be analyzed for risk issues related to the schedule (long lead hardware needs, critical path, or lack of schedule slack). Good scheduling systems provide capabilities to show resource requirements over time and to make adjustments so that the schedule is feasible with respect to resource constraints over time. The schedule can be resource loaded, thus enabling close tracking of technical parameters, milestones, and budgets to ensure that the team recognizes undesirable trends (such as an unexpected growth in lines of code or increase in its cost) early enough to take corrective action.
Once the supplier establishes firm software schedule estimates, the schedule can be baselined and controlled in the project's configuration management system. The project team needs to review these baselined schedules to ensure they are consistent with the overall project schedule.
Managing schedule variance is one of the key responsibilities of the software development team in dealing with software suppliers. The difference between the budgeted cost of work performed and the budgeted cost of work scheduled is called the schedule variance at time t. A negative value indicates that the work is behind schedule.