Health services research: what is it and what does it offer?

Over the last 20 years, clinical medicine has witnessed rapid expansion in its underlying evidence base, greater demand for accountability in clinicians' use of limited resources and increasing societal expectation for health care that confers proven benefit at reasonable cost to all eligible recipients. Health services research, also referred to as the clinical evaluative sciences, has grown in response to the need for objective empirical analysis of the modern health system's ability to deliver effective, efficient, equitable and safe care and to further the health and well-being of whole populations. In this article we provide an overview of the aims, methods and outputs of this burgeoning new discipline.