The Federal Trade Commission has proposed (PDF) withdrawing its blessing from the tar and nicotine yields included in cigarette advertisements because these machine-generated numbers are not good indicators of what smokers actually absorb:
The current yields tend to be relatively poor predictors of tar and nicotine exposure. This is primarily due to smoker compensation, i.e., the tendency of smokers of lower-rated cigarettes to take bigger, deeper, or more frequent puffs, or to otherwise alter their smoking behavior [e.g., by subconsciously covering ventilation holes] in order to obtain the dosage of nicotine they need.
The differences between the way a machine smokes in a laboratory and the way people smoke in real life have been acknowledged since the FTC first approved the "FTC method" for measuring tar and nicotine yields in 1966. But the issue has received increasing attention during the last couple of decades. After studies confirmed that the official yields are unreliable indicators of individual exposure, anti-smoking activists and trial lawyers began to argue that the numbers are inherently fraudulent, part of a scam in which tobacco companies trick consumers into believing that "light" cigarettes are less dangerous than full-strength brands. Since the research indicates that "light" cigarette smokers only partially compensate for lower yields, they should still take in less tar than they otherwise would, but any health advantage is smaller than initially hoped. A better approach would have been to increase the nicotine-to-tar ratio, rather than reducing both yields.
In response to these concerns, the FTC now wants to "withdraw its guidance...indicating that factual statements of tar and nicotine yields based on the Cambridge Filter Method generally will not violate the FTC Act." Under its proposed rule, cigarette makers could not assert or imply FTC approval of the yields, and they probably would stop using them entirely, fearing that the commission would deem them misleading. This shift in policy is overdue, but the FTC is less than forthright about its own complicity in making tar and nicotine yields ubiquitous in cigarette ads. The commission says its "1966 guidance does not require companies to state the tar and nicotine yields of their cigarettes in their advertisements or on product labels." But as epidemiologist Ronald Davis and his colleagues noted in a 1990 American Journal of Public Health article (PDF), the story is a little more complicated:
Since 1971, all major cigarette manufacturers have voluntarily disclosed the tar and nicotine yields of cigarette brands in advertisements. The cigarette industry agreed to "voluntary" disclosure after the US Federal Trade Commission (FTC) had proposed a regulation that would have required such disclosure. This agreement does not apply to cigarette packages.
So if advertising tar and nicotine yields amounts to fraud, it's a fraud that was not only endorsed but in effect required by the federal government. That did not stop the federal government from suing the tobacco companies over their "light" cigarette marketing. Nor did concerns about compensatory smoker behavior stop activists and legislators from trying to authorize the Food and Drug Administration to order reductions in nicotine content, a policy that would make cigarettes more hazardous by increasing the amount of toxins and carcinogens absorbed for a given dose of nicotine.