Problem: In 1950, Richard Doll and A. Bradford Hill published findings from a case-control study that examined a hypothesized relationship between lung cancer and smoking. They collected data from 709 lung cancer patients and 709 patients with diseases other than cancer. The patient groups were matched on age and sex. All participants received the same interview about their smoking history. Doll and Hill found that 688 of the lung cancer patients and 650 of the patients with other diseases had a history of smoking.