An overview and analysis of theories employed in telemedicine studies. A field in search of an identity.

<bold>Objectives: </bold>This study asks: What theories are employed in telemedicine studies? How might they be categorized in ways that help distinguish the knowledge base of telemedicine?<bold>Methods: </bold>Theories in use were identified from a database of telemedicine-related publications between 1990 and 2005. Eighty-three (5% of 1615) articles referred to a theoretical concept. Grounded Theory procedures were used to analyze and categorize theories, while descriptive statistics were used for supplementary information.<bold>Results: </bold>The proportion of studies with theory was 3% in 1999 and 7% in 2005. The 83 articles were dispersed among 48 of the in total 795 different journals in the original sample. Identified theories were grouped into two main categories; 'shared' (used in two or more studies) and 'lone ranger'. All of the shared theories are social science theories employed without notable adjustments to any uniquely defining features of telemedicine; diffusion, technology acceptance, health behavior, science and technology studies (STS), and economics. Theoretical concepts within the lone ranger category may well address unique features of telemedicine, but have yet to attract the attention of colleagues.<bold>Conclusion: </bold>The theories identified as 'shared' play an important role, but are inadequate in illuminating any unique features of telemedicine. The future of telemedicine as a field will need to identify its underlying theoretical components. Frameworks employed in the field of evaluation may aid in identifying the types of theories worth articulating in telemedicine. [ABSTRACT FROM AUTHOR]