The discrepancy boils down to a little provocative flourish and a statistical point of view. When discussing the cost of a regulation that will reduce a “single death” per 100 people, everybody in the at-risk population has a 1 out of 100 chance of being that additional life saved. In other words, the regulation reduces everybody’s risk by 1 percent. The “Value of a statistical life” reflects the first point of view, which is more individualistic. “Value of mortality risk reduction” (also referred to as “micro-risk reduction”) reflects the second.

The Times made a smart decision by not burdening its readers with the agency’s ongoing debate about which term to use, but journalists should be aware of the rhetoric that surrounds it—and of the EPA’s capacity to point fingers. The AP deserves credit for consistently being on top of this story, and regardless of their focus, all of the articles cited above did a fairly good job explaining what the agency is measuring and why.

Post script: Most of the articles also explained how government agencies calculate the value of a statistical life (or mortality risk reductions), which is generally based on surveys of the extra pay that workers receive for high-risk jobs, or on surveys that ask people what they would be willing to pay to avoid a certain risk. Another proposal in the EPA’s white paper suggested placing a greater value on preventing cancer deaths compared to other causes of death, because people are more afraid of cancer and would pay relatively more to avoid it.

All of the news outlets highlighted above mentioned the “cancer differential,” but only the AP dug deeper. Its report quoted risk expert David Ropeik, who called the idea “dangerous” because people tend to overestimate the risk of cancer. In an op-ed for The Washington Post, Ropeik elaborated, explaining that people tend to fear cancer more than heart disease—believing the former causes more pain and suffering—even though heart disease is much more likely to kill them. Because of such “gaps” in our perception of risk, “we push for government policies that protect us more from what we’re afraid of than from what’s more likely to kill us. Resources devoted to lesser risks aren’t available to protect us from the bigger ones - meaning that our overall risk goes up.” [Disclouse: Ropeik has contributed to The Obervatory.]

The debate about the cancer differential is related to the debate about terminology. When the EPA suggested that it begin referring to the value of “mortality risk reductions” rather than of a “statistical life,” it was trying to stress that it wasn’t putting a value on actual human beings, or, as Ropeik put it, that “these aren’t real people with faces and arms and legs. These are statistical, abstract lives.” When it came to the cancer differential, however, the agency seemed to be encouraging the opposite point of view, asking people to think about real human experience. It’s a discrepancy with a lot of nuance, but one that reporters should be aware of.

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Curtis Brainard collaborated on this article. Eliott and Griffin are the directors of the Science Media Centres in Australia and New Zealand, respectively. Kelland is Reuters health and science correspondent for Europe, the Middle East and Africa.