BOX 7-1
Efficacy and Effectiveness

Efficacy refers to the likelihood that a particular intervention will benefit patients when used under optimal or ideal experimental conditions. Such conditions are rarely met except in controlled clinical studies. An efficacious treatment is one whose effects have been shown to have a statistically significant improvement in health or well-being, typically in a randomized controlled trial (RCT).

Effectiveness refers to the likelihood that a particular intervention will benefit patients when used under usual and routine clinical practice conditions. Such conditions are generally more complex than those used in RCTs. For example, many people have coexisting conditions that alter the effect of interventions; they may not consistently follow treatment instructions; or they might be much older or younger or of different ethnicity than the people with whom the RCT was conducted.

The Committee believes that because technologies that completely replace mammography are unlikely to reach the market—at least within the next 10 years—organizations will be faced with the challenge of adopting technologies that will be used in conjunction with existing modalities. These new technologies will have to be integrated into current practice and will require the creation of new organizational routines for screening and diagnosis.

Mammography creates a high standard for any new technology. The value of any new breast cancer detection technology will be determined largely in reference to mammography. If any new technology were shown to outperform mammography for any specific groups—for example, for women whose breast density exceeds a certain threshold—then it might be adopted.

Our discussion in this chapter distinguishes among the activities of (1) technology assessment and adoption, (2) technology deployment, and (3) monitoring of technologies in use. This tripartite schema, however, is a description of best practice. Technology assessment leading up to the decision to adopt, or purchase and use, is covered in Chapter 6. In fact, many health care delivery organizations undertake technology assessment and adoption. But far fewer plan systematically for the organizational, technological, and other complementary requirements for the deployment of these technologies. Even fewer healthcare delivery organizations, in the judgment of this Committee, invest sufficiently in the monitoring of the use and effectiveness of these technologies as employed by healthcare practitioners. One of the central arguments of this chapter is the need for greater attention to these second and third activities in order to improve patient outcomes.

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