After Disney CEO Bob Iger recently said that the studios did not control MPAA ratings policy, the four major US health groups that last met with the MPAA wrote Mr. Iger confirming that the MPAA had said that the studios on MPAA's board are the policymakers; the MPAA just implements policy.
The health groups' 15 May 2015 letter, in part:
Dear Mr. Iger,
...Disney’s actions are an important step to help prevent millions of teens from beginning to smoke. In 2012 the United States Surgeon General concluded that exposure to onscreen smoking causes young people to start smoking. The Centers for Disease Control and Prevention subsequently concluded that an R rating for movies featuring smoking would be expected to reduce the number of teen smokers by nearly twenty percent preventing one million deaths from smoking among children alive today.
While we are delighted by Disney’s actions, eliminating smoking in youth rated movies is a policy that should be adopted industry-wide. In fact, our organizations have repeatedly advocated that youth rated movies should be rated R unless the movie clearly and unambiguously reflects the dangers and consequences of smoking or if it accurately depicts the behavior of an actual, historical figure. We have had discussions with the Motion Picture Association of America (MPAA), but have been told repeatedly that it will not act without direction from the studios. Since data indicate that individual movie company policies alone have not been shown to be efficient in minimizing smoking in movies, we hope Disney can take a leadership role within the MPAA to move it towards a rating system that prohibits smoking in youth rated movies….
The letter is signed by Jonathan D. Klein, American Academy of Pediatrics; Harold P. Wimmer, American Lung Association; Matthew L. Myers, Campaign for Tobacco-Free Kids; and Robin Koval, Legacy [now Truth Initiative].