EDITOR—By looking at adolescents Sargent et al studied the effect that seeing tobacco use in films had on their trying smoking.1 So many issues are not accounted for in this study that to base sweeping legislative proposals on its findings would be unwise.

For one thing, the correlation that the authors found may operate in reverse (that is, teenage smokers are more likely than non-smokers to favour a variety of passive or thrill seeking behaviours, of which greater …