Although the survey approach described above would lead to "invalid" results, I would never argue that survey studies should be thrown out and that we should only be conducting RCTs. My point is that there are strengths and limitations of various study designs, and causal inference is enhanced by having research evidence from multiple study designs. On balance, the strengths and weaknesses balance each other out, leading to a much greater ability to draw valid conclusions.
• The truth is that nicotine inhalers deliver to users the following chemicals:
According to an at Time.com: "In a hearing Wednesday afternoon that harkened back to the famous congressional Big Tobacco hearings two decades ago, Senators on the Commerce, Science and Transportation Committee eviscerated electronic cigarette executives Jason Healy, CEO of blu eCigs (owned by tobacco company Lorillard), and Craig Weiss, CEO of NJOY, leaders of the two leading e-cig brands."
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