The randomized study provides a number of important benefits that can never be realized in a survey study. Most importantly, the RCT can equalize between study groups the known and unknown confounding variables that may lead to invalid study results.

This is why I find it so troubling that some major voices in the e-cigarette community are arguing that RCTs should not be conducted and only survey studies are of value.

In this cross-sectional study, a sample of adults who smoked at any point in the past 12 months was identified from a national household survey conducted in England between 2009 and 2014. Criteria for inclusion in the study were: (1) having made a serious quit attempt in the past year; (2) having used e-cigarettes alone, NRT alone, or an unaided quit attempt during their most recent quit attempt; and (3) not having used a prescription cessation drug or behavioral counseling during their most recent quit attempt.

Jacob Sullum provides an of the literature on this topic, pointing out that there is very strong data to demonstrate that the flavors are what attract many smokers to try to quit using electronic cigarettes. You have to read his whole column, but to summarize:

1. Taking an exam

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