heart disease in 1999, compared to about 37% in 1957. For the purposes of this analysis, a focus on smokers’ perceptions is crucial to understanding the possible ways in which various harm reduction approaches, including the marketing of PREPs, may be understood or interpreted and, as a result, may affect consumer behavior.

It is now well established that perceptions of the harmfulness of smoking affect behavior. Much might be learned about the possible consequences of introducing PREPs from analysis of studies of smokers’ knowledge of the consequences of various types of tobacco products. Although Viscusi (1992, 1998) argues that smokers tend to overestimate their risks, the vast majority of research conducted to date supports the opposite conclusion. Weinstein (1999) has reviewed much of this research. In general, the work of Weinstein and others (Ayanian and Cleary, 1999; Cohn et al., 1995; Hahn and Renner, 1998; Slovic 1998, 2000) suggests the following:

• Although smokers acknowledge that smokers have higher risks for various health problems than persons who do not smoke, most smokers did not view themselves as having higher risks of heart disease or cancer compared to other adults their age.

• Smokers’ estimates of the number of years of smoking that are needed to produce health consequences increase with the number of years they have been smoking.

• Many young smokers perceive themselves to be at minimal risk from each cigarette they smoke, because they intend to stop smoking before any damage to their health occurs.

• Adolescents and adults believe that they are less likely than their peers to become addicted to cigarettes.

These findings highlight the frequently observed phenomenon of “optimism bias” or “unrealistic optimism” (Weinstein, 1999). For most hazards—and regardless of how they perceive the risks for people in general—individuals tend to perceive their own risks as less than those of other people (Weinstein, 1999; see Box 3–3).

In this report, cigarettes with tar yields on the FTC method of 15 mg or less are classified as low-yield cigarettes. In 1998, 81.9% of cigarettes consumed in the United States were low yield, up from 2.0% in 1967 (FTC