Whether media affect learning has been debated for decades. The discussion of media's effectiveness has raised questions about the usefulness of comparison studies, not only in assessing applications of technology but in other areas as well. Arguments that media do not affect learning are re-examined and issues concerning media effects on expert performance are examined. Studies of mediated expert performance in telemedicine are used to show media affect performance and suggest media contribute to learning. Media present information crucial to performing certain tasks and the use of identical or similar media in learning these tasks should have positive effects on transfer. The usefulness of media comparison studies in telemedicine is discussed and it is argued that such studies are valuable for practical decision making regarding the deployment and application of technology in training and the workplace. (Contains 3 tables and 1 figure.)