This is a serious error, as the excess incidence for 20 pack-years is much greater after 40 years of smoking 0.5 packs per day (404 × 0.5) than for 10 years at 2 packs per day (104 × 2).
This is a serious error, as the excess incidence for 20 pack-years is much greater after 40 years of smoking 0.5 packs per day (404 × 0.5) than for 10 years at 2 packs per day (104 × 2).