And furthermore, there is no evidence that electronic cigarettes are causing nonsmoking youth to become regular users. In fact, there is no evidence that any substantial proportion of nonsmoking youth who tried these products are continuing to use them regularly (more than once per month).

The truth is that there are major advantages and disadvantages of both surveys and clinical trials to examine the potential benefits of electronic cigarettes. Both types of study designs have inherent biases which can produce results that are more "favorable" or "unfavorable." This is why the methodology of published research needs to be examined so carefully. It is not so simple as to dismiss RCT evidence and accept survey evidence. One needs to consider the strengths and limitations inherent in both approaches. And at the end of the day, the only defensible approach, I believe, is that both types of studies are necessary, and we must carefully interpret and synthesize the findings from studies of multiple designs, using the totality of the evidence to make final judgments about the benefits of electronic cigarettes.

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