The GAO determined that developing a plan to deploy and operate EDSs to meet the most recent requirements could help ensure EDSs are operating most effectively and should improve checked-baggage screening; however, TSA has faced challenges in procuring the first 260 EDSs to meet 2010 requirements. Also, TSA's decision to pursue EDS procurement during data collection complicated both efforts and resulted in a delay of over 7 months for the current acquisition. Completing data collection for each phase of the 2010 requirements prior to pursuing EDS procurements that meet those requirements could help TSA avoid additional schedule delays. Although TSA has established a schedule for the current EDS acquisition, it does not fully comply with best practices, and TSA has not developed a plan to upgrade its EDS fleet. Because TSA is implementing the 2010 requirements in a phased approach, the same EDS machines may need to be upgraded multiple times. Without a plan, it will be difficult for TSA to provide reasonable assurance that the upgrades will be feasible or cost-effective. Thus, GAO recommends that TSA develop a plan to ensure that new machines, as well as those machines currently deployed in airports, will be operated at the required levels, collect explosive data before initiating new procurements, and develop a reliable schedule for the EBSP. DHS concurred with all of GAO's recommendations and has initiated actions to implement them. 2 tables and 3 figures