Defense Department weapons programs are failing to deliver capabilities as promised, even with expanding costs and schedules, the Government Accountability Office reported on Monday.

From 2000 to 2007, Defense roughly doubled its planned investment in new weapons systems from $790 billion to $1.6 trillion. Weapons systems now represent one of the largest discretionary items in the budget. The department expects to invest about $900 billion during the next five years on "development and procurement," 37 percent of which will go specifically to new major weapons systems.

Despite ballooning spending, acquisition outcomes in terms of cost and schedule have not improved, said the watchdog agency in its annual assessment of weapons acquisitions.

GAO reviewed 72 Defense programs, selected from 95 total based on dollar value, acquisition stage and congressional interest. None adequately met best practice standards for mature technologies, stable design or mature production processes by critical junctures of the acquisition, the 205-page report stated. Meeting these standards at key checkpoints is crucial to achieving planned cost, schedule and performance outcomes.

Many of the problems weapons system procurements face are the same as those of other procurement programs across government, including shifting requirements and workforce issues. GAO found that 63 percent of programs reviewed had changed requirements after development began. They encountered cost increases of 72 percent, compared with increases of 11 percent among programs that did not change requirements.

Shifting expectations in software development have particularly pronounced consequences on cost and scheduling. GAO found that half the programs had significant growth in the lines of code used to develop software, showing that managers struggle to accurately predict the amount of code needed.

Changing requirements also caused program delays, which in turn cost the government more money, GAO said. The assessed programs experienced an average delay of 21 months in delivering the first capabilities to warfighters. That was a five-month increase from the average delay in fiscal 2000, forcing the services to spend more to maintain existing systems, the report said.

From a workforce standpoint, weapons acquisitions were hampered by the revolving door for program mangers and heavy reliance on contractors to provide support functions, GAO said. According to the report, the average tenure for weapons programs started since 2001 was 17 months, less than half the length recommended in Defense policy. GAO viewed these short tenures as a threat to accountability and to the continuity of the programs.

Government auditors also questioned whether the Defense workforce had an appropriate mix of capabilities to effectively manage these programs. It was clear that the department has relied heavily on contractors to perform work previously done by federal employees, the report said. Forty-eight percent of the staff on assessed programs were made up of nongovernment employees. GAO said these contractors were taking on engineering, business and program management support roles.

One of the overarching problems with the weapons programs, according to GAO, was a deficit of a "knowledge-based acquisition process." Lack of crucial information at turning points in the project exposes programs to significant, and unnecessary, technology, design and production risks, the report said.

The Defense Department has taken steps to address these roadblocks, Gene Dodaro, acting comptroller general, wrote in a letter to Congress accompanying the report, but these steps, have yet to yield results.

"Policy without practice is not uncommon within the department, and the upcoming change in administration presents challenges in advancing progress through sustained implementation of best practices, as well as addressing new issues that may emerge," Dodaro wrote. Turning things around will require a strong consistent vision, direction and advocacy from leadership and sustained oversight by Congress, he said.

GAO made several recommendations, including balancing and prioritizing the department's portfolio of weapons system acquisitions. The watchdog group said "the right mix of weapons systems would alleviate the pressure each program now faces in winning funding from others." The report also called for strong knowledge-based business cases at the start of each program, to ensure promises on cost, schedule and performance are realistic.

Dodaro said that with weapons spending dramatically increasing and discretionary funds decreasing, now is not the time for waste.

"Every dollar spent inefficiently in developing and procuring weapons systems is less money available for many other internal and external budget priorities -- such as the global war on terror and growing entitlement programs," he wrote.

In response to a request for comment, Defense spokesman Chris Isleib said the department was planning to release a statement.