Persoskie A, et al. - Researchers undertook this longitudinal analyses of waves 2 (2014-15) and 3 (2015-16) of the prospective, national Population Assessment of Tobacco and Health Study to determine if the perception that e-cigarettes are less harmful than cigarettes forecast if dual users of cigarettes and e-cigarettes became exclusive e-cigarette users, exclusive cigarette smokers, or non-users of both product types one year later. Among US adult dual users, switching switch to exclusive e-cigarette use or to remaining dual users was more likely and the chance of switching to exclusive cigarette use one year later was less likely among those who perceived e-cigarettes as less harmful than cigarettes vs those with other perceptions of e-cigarette harm.