WHEN IS THE RIGHT TIME TO INITIATE AN ASSESSMENT OF A HEALTH TECHNOLOGY

There is currently no generally accepted formula for the optimal timin g of health technology assessments (HTAs). This paper presents some of the relevant issues and then reviews the existing literature on timin g of HTAs. It finds that the literature that specifically addresses th ese issues is limited. There is a consensus that HTAs should be initia ted at an early stage of the development of a new health technology, a nd repeated during the life cycle of the technology. However, the ques tions of reliably identifying new technologies at an early stage in th eir development and of deciding on a detectable critical point for sta rting evaluation are not resolved. It is proposed that a system of cat egorization and prioritization of health technologies should be develo ped to allow decisions to be made as to when a strongly precautionary approach is required and how the limited resources available for HTA c ould be optimally deployed.