There are some specific problems with survey studies that could lead to an overestimation of the benefits of electronic cigarettes. One major problem is that a survey study of the use of advanced vapor products would result in a severe bias towards finding a high level of effectiveness of these products. The reason? By the time smokers advance to use products like open-ended systems, they have already experienced success, fulfillment, and enjoyment with vaping. In other words, limiting the sample to users of advanced vapor products filters out the majority of e-cigarette users, who do not experience great success and therefore don't go on to the more advanced products.

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