“…Tobacco control researchers around the world often triangulate several methods to improve the precision of their estimates of the magnitude of illicit trade [ 24 ]. The volume of scientific literature is skewed towards the high- and upper middle-income countries [ 1 , 4 , 5 , 6 , 7 , 17 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ] relative to the low- and lower middle-income countries [ 11 , 24 , 35 , 36 , 37 , 38 ]. This is perhaps due to the issue of data availability and research capacity.…”