THE Defense Department says that the way the system was conceived was flawed. “We started with a Big Bang approach and put every possible requirement into the program, which made it very large and very complex,” says Elizabeth McGrath, the department’s deputy chief management officer.

E.C.S.S. was restructured many times, including three separate times in the last three years, Ms. McGrath says. “Each time, we chunked it down, breaking it into smaller pieces, focusing on specific capabilities.” But this was not enough to save the system, she says, because program managers did not succeed in imposing the short deadlines of 18 to 24 months that the department now requires for similar projects. Tight deadlines will certainly go a long way toward avoiding future billion-dollar fiascos. But much more needs to change before the department’s older software systems can be replaced.

In 2011, the nonprofit Institute for Defense Analyses, which performs independent research for the government on national security issues, issued a lengthy report on Defense Department software initiatives like E.C.S.S. It noted that modernization of the department’s software systems had been a priority for nearly 15 years, and that more than $5.8 billion had been spent through 2009 on large operational software systems, most of which were behind schedule. It recommended that the department suspend deployment of all new systems until reviews were completed.

The report cited many concerns, but the main one was a failure to meet a basic requirement for successful implementation: having “a single accountable leader” who “has the authority and willingness to exercise the authority to enforce all necessary changes to the business required for successful fielding of the software.”

I spoke last week with Paul K. Ketrick and Graeme R. Douglas, two institute researchers who were among the co-authors of the study. They said some small-scale operational systems in the Defense Department had drawn praise for successful unveilings, in the Navy and in the Defense Logistics Agency, for example.

“They got there because they had strong leadership who committed to the program and had the authority to make the changes necessary for success,” said Mr. Douglas. But “it’s rare that a single leader in the Department of Defense has the authority over the span of activities” affected by the systems, he said.