Neither the survey approach or the RCT approach is perfect. Both have major strengths and significant limitations. The best way to proceed is to conduct both types of studies and to synthesize the results across study designs, keeping in mind the methodological strengths and limitations of each individual study. Only by looking at this totality of the evidence can we draw valid scientific conclusions.

Data published last week in the American Journal of Preventive Medicine suggest that the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are doing an effective job of helping protect the cigarette industry. These data show that despite widespread marketing of electronic cigarettes, half of the adult public still thinks cigarettes are no more hazardous than the fake ones.

The CDC's statement is wrong on its face. If there is reputable evidence from former smokers that e-cigarettes helped them quit smoking, then there is indeed conclusive scientific evidence that e-cigarettes "can work" as a cessation aid.

LAST：delite smart electronic cigarette ego k ce4 clearomizer |NEXT：2014 new product made in china alibaba express wax vaporizer pen dry herb exgo w3 for wax vaporizer pen