Title: Does providing the information for rational decision making help patients make rational decisions?
Robert M. Hamm, PhD
Director, Clinical Decision Making Program
Department of Family and Preventive Medicine
University of Oklahoma Health Sciences Center
900 NE 10th St., Oklahoma City OK 73104
email: robert-hamm@ouhsc.edu
American Psychological Annual Meetings, San Francisco, August 26, 2001.
The political and ethical philosophy of empowerment has led to advocacy for physicians to share decision making with patients. An essential component of rational decision making in conditions of uncertainty, made explicit in decision theory, is knowledge of the available options, of the probabilities that these may lead to the possible outcomes, and of the utility of those outcomes. Numerous decision aids have been designed to provide such information to patients with particular diseases.
Our project sought to design a way of communicating the relevant probabilities effectively. The decision we studied is whether to get screened for prostate cancer. The information was presented in a 12 page "extended balance sheet," which explains the natural history of the disease and the screening and treatment options. Previous work has demonstrated the difficulties people have understanding probabilities, and suggested that absolute frequencies may be more understandable than relative frequencies. To convey the probabilities of cancer, of discovering cancer using screening, of treatment making a difference in outcome, and of side effects, the extended balance sheet uses a display of 1000 (initially) "smiley faces." To facilitate patients' keeping track of conditional probabilities, such as "of those treated, X% would die of prostate cancer", subsequent displays use "absolute frequencies." That is, they display the number of faces, from the original 1000, who experience each outcome. For example, if 5% of the 1000 are treated, and 10% of them die of cancer, the display would show 50 faces (those treated) with 5 "frowney faces" in a different color (those who die). The effects of this presentation format on patients' knowledge, attitudes toward screening, and subsequent behavior, as well as their satisfaction with their decision, will be a reflection of the utility of this approach.