Tanner NT, Thomas NA, Ward R, et al. - Researchers intended to assess the relationship of cigarette type with lung cancer incidence and mortality. In response to rising evidence connecting cigarette smoking as a reason for lung cancer in the 1950s, tobacco manufacturers launched filtered and “lower-tar” cigarettes to mollify consumer attention, acknowledging they did not really decrease health risks. Thus, perforating ventilation holes of differing sizes and numbers into the filter to dilute inhaled smoke became the optimum method to decrease tar yield.