In recent years, the capacity of the United States to evaluate clinical effectiveness has improved substantially. A number of public and private organizations synthesize and assess the evidence on clinical effectiveness, and many others focus on applying in real world settings the knowledge that those organizations generate. However, significant gaps in the ability to develop, synthesize, and apply the evidence on clinical effectiveness remain; and the nation faces major challenges as an array of new—and often very expensive—technologies and treatments rapidly enter the health care marketplace. As a result, the nation needs to continue to improve its capacity to assess clinical effectiveness and ensure that health care decision making is grounded in the evidence about what works.
Over the past 50 years medical knowledge has grown dramatically as breakthroughs have occurred in numerous areas of medical science, including genomics, stem cell biology, biomedical engineering, molecular biology, and immunology (Sung et al., 2003). Investments in biomedical research, both public and private, have increased steadily over time, resulting in a rapid pace of innovation in health care (Neumann and Sandberg, 1998; Zinner, 2001). Many more preventive, diagnostic, and treatment alternatives are available to patients than were available in past years; and even more are in development, including products that have resulted from research in pharmacogenomics, biotechnology, and nanotechnology (Joint Economic Committee, 2007; Walsh, 2005). Investments in research directed at understanding the human genome and the functions of genes will provide more opportunities to deliver personalized medicine, which will tailor diagnoses and therapies to an individual’s own genotype (Meadows, 2005).
At the same time, the 77 million members of the nation’s baby boom generation are nearing retirement age, and soon the health system will be confronted with patients from this large and increasingly complex cohort of individuals with multiple comorbidities, including physical and cognitive impairments (AHRQ, 2001). This will place increased demands on the health system and will add to cost pressures.
For patients and providers, as well as for society as a whole, ascertaining the effectiveness of the available preventive, diagnostic, and treatment options is becoming increasingly urgent. The expense of emerging technologies and the projected increases in consumer demand virtually ensure that cost control will be a central focus for policy makers, health plans, and others in the coming years (Clancy, 2003). Moreover, variation in treatment patterns means that, in many cases, patients will continue to receive care that deviates from standards of high quality. In the context of rapidly ris-