Acquisition program baselines embody the cost, schedule, and performance objectives for the program. The APB is approved by the milestone decision authority milestone reviews as follows: •Concept Baseline, approved at Milestone I, applied to the effort in Phase I, Demonstration and Validation. •Development Baseline, approved at Milestone II, is applied to the effort in Phase II, Engineering and Manufacturing Development. •Production Baseline, approved at Milestone III, is applied to the effort in Phase III, Production and Deployment. Each baseline must contain objectives for key cost, schedule, and performance parameters. Objectives are accompanied by minimum requirements called thresholds. Once signed by the milestone decision authority, APBs may only be changed at subsequent milestone or program reviews, or with the approval of the milestone decision authority as a response to an unrecoverable baseline deviation.