Perceived risk of electronic cigarettes compared with combustible cigarettes: direct versus indirect questioning

Tobacco companies claim that a large proportion of the population perceives potential modified risk tobacco products as equally or more harmful than cigarettes, and argue misperceptions need to be corrected using modified risk claims. However, the studies they cite predominantly use one specific measurement of comparative risk. We analysed a representative sample of US adult smokers and non-smokers to examine whether the proportion who report e-cigarettes as less harmful than regular cigarettes differs depending on how the comparative risk questions were presented.

We analysed data from the 2017 Tobacco Products and Risk Perceptions Survey. Comparative risk of cigarettes and e-cigarettes was measured in two ways: direct (single question) and indirect (by measuring perceived risk of both in separate questions and then subtracting the scores from each other).

When asked to compare harms of e-cigarettes and cigarettes directly (single question), 33.9% of participants identified e-cigarettes as less harmful than cigarettes, 36.4% reported equal harm, 4.3% said e-cigarettes were more harmful and 25.3% said 'I don't know'. When asked indirectly (separate questions), 42.1% identified e-cigarettes as less harmful than cigarettes, 23.8% said they were of equal harm, 7.1% perceived e-cigarettes to be more harmful and 27.1% did not know.

Our study offers evidence to suggest the need to use both direct and indirect risk questions when assessing the public's perceptions of harms associated with novel tobacco products.