Investigating Concurrency in Weapons Programs

Abstract : Concurrency in a weapons program -- the actual production of the weapons system while some portions of the design are still being completed -- has been a topic of debate for decades. While there have been some investigations into certain programs that point to concurrency as a possible culprit for some cost growth, there have been few systematic studies that measure how closely related the two are. A 1988 Congressional Budget Office (CBO) study is one of the few studies that actually did try to measure this relationship. Examining 14 major programs that were deployed in the 1970s, the CBO found that the statistical relationship between concurrency and cost growth was very low. The relationship was even lower for schedule slippage. Another study conducted by the RAND Corporation in 2006, using the same definition as the CBO study, also identified the possibility that concurrency does not have an impact on cost growth. We examined the relationship between cost growth and concurrency again in response to a request by assistant secretary of the Navy for research, development, and acquisition. In contrast to the CBO and RAND studies, we defined concurrency as the percentage share of RDT&E money that was being spent while procurement dollars were also being spent. Our results, based on examining 28 programs across all Services, are very similar to those of the CBO and RAND studies with one surprising exception: While from a purely statistical point of view we found that the relationship between both planned and actual concurrency and cost growth was very weak, in both cases, there seems to be a "sweet spot" of about 30 percent concurrency. That is, programs that plan on spending 30 percent of RDT&E funds while concurrently spending procurement funds actually experience the lowest average cost growth. In sum, our study suggests that programs should plan for some moderate level of concurrency (somewhere around 30 percent) and then stick to the plan.