This report is one of a series from a RAND Project AIR FORCE project, "The Cost of Future Military Aircraft: Historical Cost Estimating Relationships and Cost Reduction Initiatives." The purpose of the project is to improve the tools used to estimate the costs of future weapon systems. It focuses on how recent technical, management, and government policy changes affect cost. This report focuses on the accuracy of cost estimates. For our analysis, we used a very specific sample of Selected Acquisition Report (SAR) data, namely only programs that are complete or are nearly so. The analysis indicates a systematic bias toward underestimating the costs and substantial uncertainty in estimating the final cost of a weapon system. In contrast to the previous literature, the cost growth was higher than previously observed. We also found few correlations with cost growth, but observed that programs with longer duration had greater cost growth and electronics programs tended to have lower cost growth. Although there were some differences in the mean cost growth factors among the military departments, the differences were not statistically significant. While newer programs appear to have lower cost growth, this trend appears to be due to factors other than acquisition policies.

In recent decades, there have been numerous attempts to rein in the cost growth of U.S. Department of Defense (DoD) acquisition programs. Cost growth is the ratio of the cost estimate reported in a program's final Selected Acquisition Report (SAR) and the cost-estimate baseline reported in a prior SAR issued at a particular milestone. Drawing on prior RAND research, new analyses of completed and ongoing weapon system programs, and data drawn from SARs, this study addresses the following questions: What is the cost growth of DoD weapon systems? What has been the trend of cost growth over the past three decades? To address the magnitude of cost growth, it examines cost growth in completed programs; to evaluate the cost growth trend over time, it provides additional analysis of a selection of ongoing programs. This sample of ongoing programs permits a look at growth trends in the more recent past. Changes in the mix of system types over time and dollar-weighted analysis were also considered because earlier studies have suggested that cost growth varies by program type and the cost of the program. The findings suggest that development cost growth over the past three decades has remained high and without any significant improvement.

This analysis uses data from Selected Acquisition Reports to determine the causes of cost growth in 35 mature major defense acquisition programs. Four major sources of growth are identified: (1) errors in estimation and scheduling, (2) decisions by the government, (3) financial matters, and (4) miscellaneous. The analysis shows that more than two-thirds of cost growth (measured as simple averages) is caused by decisions, most of which involve quantity changes, requirements growth, and schedule changes.

Joint Vision 2020 is the conceptual template for how we will channel the vitality of our people and leverage technological opportunities to achieve new levels of effectiveness in joint warfighting.