As part of an ambitious plan to transform its training practices, the U.S. Army is in the process of converting 525 training courses to distributed learning (DL) by the year 2010. DL provides decentralized training using one or more information and communication technologies or a combination of classroom training and technology-mediated training. This report reviews the state of research on learning outcomes in DL, particularly in comparison to residential learning (RL), which is the current standard for training. The report also presents a series of recommendations concerning (1) the development of a research agenda focused on the effects of variations in the design of DL rather than the comparison of DL and RL, (2) methodological strategies for improving the quality of research on DL, and (3) policies to support the design, implementation, and evaluation of DL. Adopting these recommendations can help the Army use DL to realize its vision of transforming training and providing life-long learning for multiskilled soldiers.