Summary: By overestimating savings and understating costs, the Pentagon has included in its Future Years Defense Program more programs than spending plans can support--more than $150 billion in overprogramming from the fiscal year 1995-99 period, according to GAO estimates. The Defense Department's (DOD) current Future Years Defense Program is overprogrammed by about $20 billion when compared with the Administration's fiscal year 1995 budget submissions. GAO found another $1.5 billion in negative adjustments in the research and development account. GAO believes that it is inconsistent with congressional intent for DOD to use negative adjustments to unspecified programs to balance Future Years Defense Program funding estimated with those in the President's budget. This overprogramming is not new. Since 1984, GAO has consistently disclosed that DOD employs a systemic bias toward overly optimistic planning. The use of optimistic planning assumptions has led to program instability, costly program stretch-outs, and program terminations.