Each key FAA NextGen project has an individual "metric" to measure how its development is progressing. But as the Government Accountability Office (GAO) warned recently, the FAA doesn't use "lateral" metrics that would allow senior management to track the relative progress of separate projects that must eventually work together to make NextGen happen. Without informed management monitoring of the many intertwining NextGen projects, their operational outcomes could be impossible to predict or coordinate, the GAO stated. Meanwhile, tests of the FAA's en route automation modernization (Eram) system, NextGen's future computer backbone, with real traffic were abandoned after more than 15,000 software issues arose, of which 1,400 are still unresolved, including 200 "critical" issues.