 So, health technology assessment is also called HDA. HDA is the systematic study of the clinical effectiveness, cost-effectiveness and social and ethical impacts of a health technology on the lives of patients and a healthcare system. This can be drugs, devices, procedures, care settings and so on. Its main purpose is to inform healthcare policy makers. Health technology assessment agencies vary but most look at the health benefit and risk of using a particular technology. HDA also looks at costs and any wider impacts that the technology might have on a population or on society.