Translation is the process of turning observations in the laboratory, clinic, and community into interventions that improve the health of individuals and the public — from diagnostics and therapeutics to medical procedures and behavioral changes.
The translational science spectrum (T1-T4) represents each stage of research along the path from the biological basis of health and disease to interventions that improve the health of individuals and the public. Each stage builds upon and informs the others. Patient involvement is a critical feature of all stages in translation.
T1 - the process of applying discoveries generated in preclinical laboratory research to experimental studies in primates and human participants
T2 - research allows investigators to extend limited clinical observations into controlled environments (e.g., phase III clinical trials) to establish evidence-based efficacy under optimal settings
T3 - investigators establish how specific prevention and treatment strategies work in real-world community settings (e.g., phase IV trials), assessing effectiveness, cost-effectiveness, and the influence on health practice. Important health agenda in the community needs to be translated back to the clinic and bench, respectively, to inform the processes of relevant application and basic discovery; these studies are considered as reverse T3 projects.
T4 - research involves the application of validated, health practices from communities to their impact on human populations. The latter is the ultimate pay-off for national and institutional investments into the translational research platform.
NIH Translational Science Fact Sheet