Prevention implies a future orientation. By engaging in preventive actions, individuals attempt to affect the likelihood of developing a health problem, delaying the development of a health problem, or reducing the severity of the health problem when it develops. An investment in preventive care today is expected to change a person's future health trajectory. At first glance, how expected trajectories impact how various preventive actions are viewed by older adults may seem relatively straightforward. Older persons have shorter life expectancies and hence may view the likelihood of benefit differently from younger people. The differences in perceived possible benefits between the age groups would logically lead to differences in how the age groups value preventive services. Organizations like the U.S. Preventive Services Task Force (USPSTF), charged with making recommendations about preventive services, would likely want to consider the values older people place on various preventive activities as part of the process of formulating recommendations. This project was requested by the USPSTF because clinical preventive services are increasing in importance as the U.S. population ages. However, there are challenges in evaluating the evidence for preventive services in older adults and in applying the evidence to developing recommendations specific to older adults; perceived benefits and harms may differ from the general population due to decreasing life expectancy, increasing comorbidities, and competing causes of death in older adults. A specific challenge is determining when the net balance of perceived benefits and harms turns negative; that is, when do the harms begin to outweigh the benefits? One important consideration is how patient values affect the determination of benefits and harms of clinical preventive services. Uncertainty is a critical issue facing patients and providers in deciding a course of action for prevention. There is uncertainty regarding the potential benefits and harms an older person may receive from any particular preventive service. There is also uncertainty regarding the place of a particular preventive service, or the array of preventive services, within the context of other health concerns older persons may face. Such uncertainty may arise from the physiology of aging, the presence of a single chronic illness or multiple conditions, or the risk for mortality. The presence of uncertainty amplifies the importance of understanding values and preferences, because those values and preferences may end up mattering more, potentially driving the choices in directions different from what would have transpired in the case of certainty. The aim of this review is to provide to the USPSTF a compendium of general information that can be used as a resource when the Task Force is deliberating recommendations on preventive care for older persons and the decision to engage or not engage in a preventive behavior. The following key questions are the basis for this review. KQ 1. How do older adults value the potential benefits of primary and secondary clinical preventive services, including reductions in morbidity and mortality, improvements in quality of life, maintenance of independence, and functional ability? Does cognitive ability or functional limitation affect how older adults value the potential benefits? KQ 2. What attitudes do older adults have about potential harms of clinical preventive services? KQ 3. What value do older adults place on the receipt of clinical preventive services? KQ 4. How do older adults understand the balance of risks and benefits from clinical preventive services? KQ 5. How should clinicians engage in shared decisionmaking related to clinical preventive services in older adults?