Cross-validation of four different survey methods used to estimate illicit cigarette consumption in Brazil.

Objective: To cross-validate estimates of the size of the illicit cigarette trade based on the results of four different survey methods.
Methods: In 2018/2019, four non-industry-funded, large-scale studies were conducted in selected Brazilian cities: packs discarded in household garbage/PDG (1 city), packs littered in the streets/PLS (5 cities), a phone survey of tobacco users' purchase behaviors/VIGITEL (5 cities), and a face-to-face household survey of tobacco users' purchase behaviors/FTF-household (2 cities). The proportions of illicit cigarettes consumed were based on the price paid by smokers in their last purchase (VIGITEL or FTF-household) and/or direct observation of brand names and health warnings (PDG, PLS or FTF-household).
Results: Based on PLS, the share of packs that avoided taxation ranged from 30.4% (95% CI 25.6% to 35.7%) in Rio de Janeiro to 70.1% (95% CI 64.6% to 75.0%) in Campo Grande; and PDG conducted in Rio de Janeiro found an even lower proportion point estimate of illicit cigarette use (26.8%, 95% CI 25.1% to 28.6%). In FTF-household, the share of illicit cigarette consumption based on the self-reported price ranged from 29.1% (95% CI 22.4% to 35.7%) in Rio de Janeiro to 37.5% (95% CI 31.2% to 43.7%) in São Paulo, while estimates based on pack observation ranged from 29.9% (95% CI 23.3% to 36.5%) in Rio de Janeiro to 40.7% (95% CI 34.3% to 47.0%) in São Paulo. For all cities, VIGITEL presented the lowest levels of illicit consumption, and most illicit brands were produced in Paraguay.
Conclusions: Small differences in the estimated levels of illicit trade across methods were found, except for the phone survey. The cross-validation of estimates from independent studies is important to help effectively implement tobacco excise tax policy in Brazil and other low-income and middle-income countries.
Competing Interests: Competing interests: None declared.
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