Doubting the Health Harms of Air Pollution — Not a “Mistake,” but Not “Just Science” Either
I’m going to attempt to do here what a science reporter recently failed utterly to do; to refrain from spinning a lurid private morality play, and actually try to explain the substance of a public moral (and scientific) dispute. The failure in question concerns a four-part series the Center for Public Integrity (CPI) published online on Dec. 12 — about the “government’s secret alliance with Big Oil” and the petroleum lobby’s long-term sponsoring of one risk analyst to foment doubt about whether air pollution (specifically, ozone and fine particulate pollution) causes any harm at all to human health at current levels. One part of the series focuses on Dr. Louis Anthony (“Tony”) Cox, a Denver-based consultant newly-appointed by EPA Administrator Scott Pruitt to head EPA’s Clean Air Act Science Advisory Committee, and quotes me (a professor at a school of public health and a law school, and the former chief regulatory official at the U.S. Occupational Safety and Health Administration).
The CPI reporter (Jie Jenny Zou) accurately described Tony and me as “two friends [whose] views on what should or shouldn’t be regulated couldn’t be further apart.” Indeed, we were college classmates more than 40 years ago and have kept in close touch since. She also got it almost right (but quite wrong) when she wrote that I “count Cox among an elite few who have the credentials for risk analysis, an amalgam of health sciences, economics, policy-making, and statistics.” Actually, I emphasized at the outset that while more and more worthy risk analysts are coming to the field with good credentials in one or two of its component disciplines, I’ve always looked up to Tony as one of the few who planned his undergraduate and graduate studies and work experiences so as to be broadly proficient (that is, having the highest credentials) in all these raw materials.
Ms. Zou asked me to comment on a 120-page slide presentation Tony recently presented to a group of state and federal judges about different kinds of causal and non-causal relationships in regulatory science (note: an earlier version of this slide show is here). Tony makes two fundamental points: (1) that it is possible for high levels of pollutant X to cause, or appear to cause, higher levels of disease Y, and yet future regulations to reduce X might not reduce Y; and (2) that judges should “insist on evidence” from regulatory agencies that pollution controls have reduced or will reduce disease, and “exclude evidence” that does not meet this standard.
I found Tony’s presentation profoundly disturbing, for five basic reasons. None of these have to do with the propriety of his trying to influence judges — I applaud evidence-based advocacy as long as the evidence is credible and the advocacy is honestly disclosed as such.
- Something is amiss that not one word in the 120 slides mentioned the fact that agencies’ estimates of regulatory cost are also plagued with assumptions that could invalidate key relationships. After all, where do we get the ideas that prices will rise or that jobs will be destroyed if we require pollution controls? From economic modeling, of course — where claims of future causality at best come from observations of past associations. So encouraging judges to ignore benefits but to swallow whole accusations of cost is a half-right lecture, which is to say a wholly incomplete piece of advocacy;
- Cox identifies legitimate problems such as confounding (a spurious association between exposure and disease, actually caused by an unobserved third factor linked to both), but failed to tell the judges that epidemiologists have cared about these problems for many decades and have refined statistical methods to reveal and correct for them;
- He, of course, counsels for better information, for waiting to decide until we can resolve these important unknowns. This, of course, is both respectful of the science and (conveniently?) a recipe for inaction over action. It feeds into a legal/regulatory system in which the status quo allows exposures to continue unabated until a final decision is made that the free market is (oops!) creating health and environmental costs in excess of its economic benefits;
- Tony is only interested in how government might regulate harms as causal when they are not, and so he fails utterly to mention the mirror-image problem of ignoring harms as non-causal when they are. In fact, I can easily argue that risk analysis currently sets a higher bar to guard against these false negatives than it needs to be strengthened to prevent false positives. Consider the perennial rule that an association found in an epidemiology study cannot be considered “real” unless it is statistically significant at the p<0.05 level. That means that an environmental exposure that appears to double the risk of disease cannot be regulated if there is a 5 percent chance that the exposure does not increase risk at all. I support this kind of gatepost, but it seems ironic (these days, a euphemism for “deliberate”) that Tony wants us to make regulations less stringent when we aren’t 100% sure an effect is causal, but isn’t interested in changing our practice of doing nothing when we are “only” 90% sure an association is real.
- Most importantly, Tony has waded waist-deep into the Big Muddy of decision-making under uncertain consequences, a terrain that simply cannot be navigated without imposing value judgments upon the choice. He is part of a long and frustrating tradition of above-the-fray scholars who believe (or claim to believe) that they are merely providing “objective” advice, yet nothing could be further from the truth. A doctor who says that a patient should get an amniocentesis (because she is above the age where the odds of having a child with Down syndrome exceed the odds of the test itself causing a miscarriage) is forcing her to regard the consequences of the two bad outcomes as equally dire, when any other weighing of the two outcomes could be her true and valid preference. A consultant who says that you should find the “best estimate” of how long it will take to drive to the airport to catch your flight is telling you — without telling you! — that you regard being 4 minutes late to the gate as better than being 5 minutes early (the former mistake is “closer to the right answer” than the latter). So when Tony tells judges that they should regard a “possibly causal” exposure as less worthy of intervention than a “known causal” one, he is steering them to the view that false positives (or over-regulation) are to be avoided — and by counseling them to “exclude” harms not proven causal, to the view that false positives are far more dire than the opposite. This is a perfectly defensible value judgment, but it is indefensible to hide it by failing to mention that any other weighing of the two is also valid. Maybe ozone and fine particles aren’t as dangerous as the face-value epidemiologic studies would indicate: but if we regulate them less stringently (or not at all) because of real or manufactured doubt, we would be balancing the costs of error in strict and profound ways, none of which Tony wants to talk about. In my long experience, when experts don’t want to admit their values it’s because they prefer to impose their values covertly, and prefer to belittle those who advocate for different values and who do so transparently.
Despite this rich ground for our scholarly divide, all that readers of CPI’s story about Tony learned about our disagreements is that I apparently think he has made “a stupid mistake.” I have no recollection of using those words in the hours of Q&A I had with Ms. Zou, though I initially had no reason to doubt her memory. But I thought it was poor journalism — unfair to me and to the readers — to refer to an unnamed “mistake” by leaving out the predicate of the sentence(s) I may have offered. What mistake(s)? Obviously, as I told her boss, it makes the source, and the writer, look desperate and not credible to accuse someone of some vague and unrevealed error. But he responded that there was no need for the story to explain, because it was obvious to his readers that I was instead quoted making the omnibus criticism that Tony’s “mistake” was in taking industry money to lecture to judges, not anything in the content of his presentation.
That may be CPI’s criticism, but it is the exact opposite of mine, and I made that clear in the very first minute I spoke with the reporter. I told her that while I’m no fan of potentially undisclosed conflicts of interest, other sources are more qualified to opine on that, while I want to focus on why some advocates are misleading or disingenuous in their conclusions. CPI refused repeated entreaties to provide me with audio or notes on what I must have said the “stupid mistake” was, which now leaves me wondering which words indeed were mine and which were misattributed to me as well as surely taken out of context.
Do I think my old friend Tony has a jaundiced view of public-health causality, and is not willing to admit that discounting public concern over something not known to meet his high standards of “causal” is his way of imposing deep and hidden value judgments onto society? That I do; but I come away from this personal lesson in dealing with reporters with more regret that a “center for public integrity” doesn’t have more private integrity in its work.
Originally published at medium.com on January 3, 2018.