According to the Center for Tobacco Policy Research, recent research has shown that warning labels on cigarette boxes give people "greater knowledge about the risks of smoking," they have a "greater negative affect toward smoking cues," they "reduce attractiveness of smoker images and of cigarette packaging," they "reduce intention to purchase cigarettes," and they "increase intention quit rates and actual quit rates." Warning labels that are most effective are "prominent in size, graphics, color and contrast." Warning labels effect may be modest but if they help only one person then they are completely worth it. The warning labels will be more effective if they are designed for a "particular audience" or a "particular goal." This source has great evidence in the benefits of warning labels so I will definitely use this in my research paper.
Center for Tobacco Policy Research. (2007). Do warning labels work? Lessons from tobacco
control. Retrieved from http://ctpr.wustl.edu/documents/warning_labels_2007.pdf