This article examines the challenges faced by developers of youth drug abuse prevention programs in transporting scientifically proven or evidence-based programs into natural community practice systems. Models for research on the transfer of prevention technology are described with specific emphasis given to the relationship between efficacy and effectiveness studies. Barriers that impede the successful integration of efficacy methods within effectiveness studies (e.g., client factors, practitioner factors, intervention structure characteristics, and environmental and organizational factors) are discussed. We present a modified model for program development and evaluation that includes a new type of research design, the hybrid efficacy-effectiveness study that addresses program transportability. The utility of the hybrid study is illustrated in the evaluation of the Early Risers "Skills for Success" prevention program.