An epidemiologic study was undertaken to determine the relationship between alcohol
consumption and the occurrence of laryngeal cancer. Estimates of mean levels of per capita
alcohol consumption in New York State and Illinois were compared to the incidence rates of
laryngeal cancer in these two states during the same time frame. Incident cases of laryngeal
cancer were identified from the state cancer registries. The incidence rates of laryngeal cancer
were shown to increase with increasing per capita consumption of alcohol. What type of study
Which of the following statements describes a major advantage of randomly assigning study
participants to the different treatment groups in a clinical trial?