This is a guest post by Simon Kiss.
If the science is so conflicted, why did some jurisdictions adopt regulatory bans on products made from BPA while others did not? Before the United States ever took action at the federal level (at the request of the plastics industry, not environmental groups, mind you), Canada and a number of US state legislatures began doing so. When I initially got interested in this case, it seemed that the Canadian media were covering the issue far more than in other countries. This proved to be the case, but I also thought that the varied legislative paths experienced in US states offered the opportunity for a natural experiment testing the effects of media coverage about BPA on whether US state legislatures considered or adopted bans on products made with BPA.
The short answer is that media attention to BPA helped initiate and sustain attempts at regulation. Thus, BPA regulation did not follow a traditional path of diffusion—whereby one state’s actions lead other states to act similarly. Instead, local news stories within that state helped to produce a response from state lawmakers.
My analysis—recently published here (ungated)—combines information on news stories about BPA in major daily newspapers with information on state legislative activity regarding BPA. After account for several other factors besides media coverage I find that news stories were consistently linked to the chance that a state legislature would consider legislation banning products made with BPA. And even though this coverage did not affect the chances that the legislature would ban BPA, in 8 of the 9 states that have banned it, the ban only passed after a previous legislative session had first considered the ban. Thus, news coverage appears to have contributed indirectly to several outright bans.
These findings have two important lessons. First, at the state level, the policy response to concerns about BPA is driven more by media coverage than by scientific concern. This suggests that, second, media coverage of complex risks can drive policy-makers to action even in the absence of scientific consensus. Thus, journalists must be cautious in describing the research—lest their coverage help to produce an overreaction to uncertain science.